diff --git a/lib/persistentRndStorage.js b/lib/persistentRndStorage.js
index 515edb7..9aa1a79 100644
--- a/lib/persistentRndStorage.js
+++ b/lib/persistentRndStorage.js
@@ -58,6 +58,12 @@
 		settings.on("storePersistentRnd", function({newValue}){
 			settings.persistentRndStorage = newValue? JSON.stringify(scope.persistentRnd): "";
 		});
+		
+		logging.message("register contextual identities removal");
+		browser.contextualIdentities.onRemoved.addListener(function(details){
+			logging.message("Contextual identity", details.contextualIdentity.cookieStoreId, "removed.");
+			clearContainerData(details.contextualIdentity.cookieStoreId);
+		});
 	};
 
 	const getInterval = function(){
@@ -133,7 +139,33 @@
 		}
 		broadcast({"canvasBlocker-set-domain-rnd": {domain, incognito, rnd}});
 	}
-
+	function clearDomainData(domain){
+		logging.verbose("clear domain rnd for ", domain);
+		delete scope.persistentIncognitoRnd[domain];
+		settings.persistentIncognitoRndStorage = JSON.stringify(scope.persistentIncognitoRnd);
+		delete scope.persistentRnd[domain];
+		settings.persistentRndStorage = JSON.stringify(scope.persistentRnd);
+	}
+	
+	function clearContainerData(cookieStoreId){
+		logging.verbose("clear container rnd for ", cookieStoreId);
+		Object.keys(scope.persistentRnd).forEach(function(domain){
+			if (domain.startsWith(cookieStoreId + "@")){
+				delete scope.persistentRnd[domain];
+			}
+		});
+		settings.persistentRndStorage = JSON.stringify(scope.persistentRnd);
+		
+		Object.keys(scope.persistentIncognitoRnd).forEach(function(domain){
+			if (domain.startsWith(cookieStoreId + "@")){
+				delete scope.persistentIncognitoRnd[domain];
+			}
+		});
+		settings.persistentIncognitoRndStorage = JSON.stringify(scope.persistentIncognitoRnd);
+	}
+	
 	scope.clear = clear;
 	scope.setDomainData = setDomainData;
+	scope.clearDomainData = clearDomainData;
+	scope.clearContainerData = clearContainerData;
 }());
\ No newline at end of file
diff --git a/manifest.json b/manifest.json
index 13c8d2d..c5d71d4 100644
--- a/manifest.json
+++ b/manifest.json
@@ -88,6 +88,7 @@
 		"activeTab",
 		"webRequest",
 		"webRequestBlocking",
+		"contextualIdentities",
 		"cookies"
 	],
 	
diff --git a/releaseNotes.txt b/releaseNotes.txt
index 7cf1dc4..f760273 100644
--- a/releaseNotes.txt
+++ b/releaseNotes.txt
@@ -5,6 +5,7 @@ Version 0.5.11:
 	new features:
 		- added auto update for beta versions
 		- options: made sections collapsible
+		- clear persistent rng data if a container is deleted
 	
 	fixes:
 		- improved protection of (i)frame properties