diff --git a/src/Profiles/BagItProfile.php b/src/Profiles/BagItProfile.php
index a6991b1..e1e900b 100644
--- a/src/Profiles/BagItProfile.php
+++ b/src/Profiles/BagItProfile.php
@@ -337,16 +337,11 @@ public function getBagInfoTags(): array
     /**
      * @param array $bagInfoTags Parsed profile Bag-Info sections
      * @return BagItProfile The profile object.
-     * @throws ProfileException If invalid options are specified for a tag.
      */
     private function setBagInfoTags(array $bagInfoTags): BagItProfile
     {
-        $expectedKeys = ['required' => 0, 'values' => 0, 'repeatable' => 0, 'description' => 0];
         $this->profileBagInfoTags = [];
         foreach ($bagInfoTags as $tagName => $tagOpts) {
-            if (count(array_diff_key($tagOpts, $expectedKeys)) > 0) {
-                throw new ProfileException("Invalid tag options for $tagName");
-            }
             if (self::matchStrings('BagIt-Profile-Identifier', $tagName)) {
                 $this->profileWarnings[] = "The tag BagIt-Profile-Identifier is always required, but SHOULD NOT be " .
                 "listed under Bag-Info in the Profile.";
diff --git a/src/Profiles/ProfileTags.php b/src/Profiles/ProfileTags.php
index 2d0adba..1c66c68 100644
--- a/src/Profiles/ProfileTags.php
+++ b/src/Profiles/ProfileTags.php
@@ -13,6 +13,11 @@
  */
 class ProfileTags
 {
+    /**
+     * Array with keys matching optional keys from specification, all other keys are system specific.
+     */
+    private const SPEC_TAGS = ['required' => 0, 'values' => 0, 'repeatable' => 0, 'description' => 0];
+
     /**
      * @var string
      */
@@ -38,6 +43,11 @@ class ProfileTags
      */
     private string $description = "";
 
+    /**
+     * @var array<string, mixed>
+     */
+    private array $otherOptions = [];
+
     /**
      * ProfileTags constructor.
      * @param string $tag
@@ -95,14 +105,43 @@ public function getDescription(): string
         return $this->description;
     }
 
+    /**
+     * Return any tags defined in the BagItProfile but not in the specification.
+     * @return array<string, string> Array of tagName => tagValue
+     */
+    public function getOtherTagOptions(): array
+    {
+        return $this->otherOptions;
+    }
+
+    /**
+     * Set the other tag options.
+     * @param array $tagOptions Array of optionName => optionValue
+     */
+    protected function setOtherTagOptions(array $tagOptions): void
+    {
+        $this->otherOptions = $tagOptions;
+    }
+
+    /**
+     * Create a ProfileTags object from a JSON array.
+     * @param string $tag Tag name
+     * @param array<string, string> $tagOpts Tag options
+     * @return ProfileTags The created object.
+     */
     public static function fromJson(string $tag, array $tagOpts): ProfileTags
     {
-        return new ProfileTags(
+        $profileTag = new ProfileTags(
             $tag,
             $tagOpts['required'] ?? false,
             $tagOpts['values'] ?? [],
             $tagOpts['repeatable'] ?? true,
             $tagOpts['description'] ?? ""
         );
+        $otherTags = array_diff_key($tagOpts, self::SPEC_TAGS);
+        if (count($otherTags) > 0) {
+            $profileTag->setOtherTagOptions($otherTags);
+        }
+        return $profileTag;
     }
 }
diff --git a/tests/Profiles/BagProfileTest.php b/tests/Profiles/BagProfileTest.php
index 639fca5..0ccf2fc 100644
--- a/tests/Profiles/BagProfileTest.php
+++ b/tests/Profiles/BagProfileTest.php
@@ -37,7 +37,7 @@ public function testValidateBag1(): void
      * @group Profiles
      * @covers ::setBagInfoTags
      */
-    public function testInvalidBagInfoTags(): void
+    public function testOptionalBagInfoTags(): void
     {
         $profileJson = <<< JSON
 {
@@ -65,9 +65,21 @@ public function testInvalidBagInfoTags(): void
   ]
 }
 JSON;
-        $this->expectException(ProfileException::class);
-        $this->expectExceptionMessage("Invalid tag options for Source-Organization");
-        BagItProfile::fromJson($profileJson);
+        $profile = BagItProfile::fromJson($profileJson);
+        $this->assertTrue($profile->isValid());
+        $this->assertArrayEquals(["source-organization"], array_keys($profile->getBagInfoTags()));
+        $tag = $profile->getBagInfoTags()["source-organization"];
+        $this->assertEquals("Source-Organization", $tag->getTag());
+        $this->assertTrue($tag->isRequired());
+        $this->assertArrayEquals(["Simon Fraser University", "York University"], $tag->getValues());
+        $this->assertEquals("", $tag->getDescription());
+        $this->assertTrue($tag->isRepeatable());
+        $this->assertArrayEquals(
+            [
+                "help" => "This is the organization that originally created the bag."
+            ],
+            $tag->getOtherTagOptions()
+        );
     }
 
     /**
@@ -486,4 +498,84 @@ public function testAddSameProfileTwice(): void
         $bag->removeBagProfile("http://www.library.yale.edu/mssa/bagitprofiles/disk_images.json");
         $this->assertCount(0, $bag->getBagProfiles());
     }
+
+    /**
+     * @group Profiles
+     * @covers \whikloj\BagItTools\Bag::addBagProfileByJson
+     * @covers \whikloj\BagItTools\Bag::addBagProfileInternal
+     * @covers \whikloj\BagItTools\Bag::removeBagProfile
+     */
+    public function testAddDifferentProfiles(): void
+    {
+        $profile1 = file_get_contents(self::$profiles . "/bagProfileFoo.json");
+        $profile2 = file_get_contents(self::$profiles . "/bagProfileBar.json");
+        $profile3 = file_get_contents(self::$profiles . "/btrProfile.json");
+        $bag = Bag::create($this->tmpdir);
+        $this->assertCount(0, $bag->getBagProfiles());
+        $bag->addBagProfileByJson($profile1);
+        $this->assertCount(1, $bag->getBagProfiles());
+        $bag->addBagProfileByJson($profile2);
+        $this->assertCount(2, $bag->getBagProfiles());
+        $bag->addBagProfileByJson($profile3);
+        $this->assertCount(3, $bag->getBagProfiles());
+        // Add profile a second time has no effect.
+        $bag->addBagProfileByJson($profile2);
+        $this->assertCount(3, $bag->getBagProfiles());
+        $this->assertArrayEquals(
+            [
+                "http://canadiana.org/standards/bagit/tdr_ingest.json",
+                "https://github.com/dpscollaborative/btr_bagit_profile/releases/download/1.0/btr-bagit-profile.json",
+                "http://www.library.yale.edu/mssa/bagitprofiles/disk_images.json",
+            ],
+            array_keys($bag->getBagProfiles())
+        );
+        // Remove profiles.
+        $bag->removeBagProfile("http://canadiana.org/standards/bagit/tdr_ingest.json");
+        $this->assertCount(2, $bag->getBagProfiles());
+        $bag->removeBagProfile(
+            "https://github.com/dpscollaborative/btr_bagit_profile/releases/download/1.0/btr-bagit-profile.json"
+        );
+        $this->assertCount(1, $bag->getBagProfiles());
+        // Remove profile that doesn't exist in bag has no effect
+        $bag->removeBagProfile("http://canadiana.org/standards/bagit/tdr_ingest.json");
+        $this->assertCount(1, $bag->getBagProfiles());
+        $bag->removeBagProfile("http://www.library.yale.edu/mssa/bagitprofiles/disk_images.json");
+        $this->assertCount(0, $bag->getBagProfiles());
+    }
+
+    /**
+     * @group Profiles
+     * @covers \whikloj\BagItTools\Bag::clearAllProfiles
+     */
+    public function testClearAllProfiles(): void
+    {
+        $profile1 = file_get_contents(self::$profiles . "/bagProfileFoo.json");
+        $profile2 = file_get_contents(self::$profiles . "/bagProfileBar.json");
+        $profile3 = file_get_contents(self::$profiles . "/btrProfile.json");
+        $bag = Bag::create($this->tmpdir);
+        $this->assertCount(0, $bag->getBagProfiles());
+        $bag->addBagProfileByJson($profile1);
+        $bag->addBagProfileByJson($profile2);
+        $bag->addBagProfileByJson($profile3);
+        $this->assertCount(3, $bag->getBagProfiles());
+        $bag->clearAllProfiles();
+        $this->assertCount(0, $bag->getBagProfiles());
+    }
+
+    /**
+     * @group Profiles
+     * @covers \whikloj\BagItTools\Bag::getBagProfiles
+     */
+    public function testGetBagProfile(): void
+    {
+        $profile = file_get_contents(self::$profiles . "/bagProfileBar.json");
+        $bag = Bag::create($this->tmpdir);
+        $bag->addBagProfileByJson($profile);
+        $testProfiles = $bag->getBagProfiles();
+        $this->assertCount(1, $testProfiles);
+        $key = key($testProfiles);
+        $val = current($testProfiles);
+        $this->assertEquals("http://canadiana.org/standards/bagit/tdr_ingest.json", $key);
+        $this->assertInstanceOf(BagItProfile::class, $val);
+    }
 }