diff --git a/toolkit/components/url-classifier/Classifier.h b/toolkit/components/url-classifier/Classifier.h
index e8bf890dc95a..88eedbf1898e 100644
--- a/toolkit/components/url-classifier/Classifier.h
+++ b/toolkit/components/url-classifier/Classifier.h
@@ -84,8 +84,6 @@ public:
    */
   nsresult ApplyFullHashes(nsTArray<TableUpdate*>* aUpdates);
 
-  nsresult CacheCompletions(const CacheResultArray& aResults);
-  uint32_t GetHashKey(void) { return mHashKey; }
   /*
    * Get a bunch of extra prefixes to query for completion
    * and mask the real entry being requested
diff --git a/toolkit/components/url-classifier/LookupCache.h b/toolkit/components/url-classifier/LookupCache.h
index c46445d5fc17..733a8e0d08ca 100644
--- a/toolkit/components/url-classifier/LookupCache.h
+++ b/toolkit/components/url-classifier/LookupCache.h
@@ -82,7 +82,6 @@ public:
   // True as long as this lookup is complete and hasn't expired.
   bool mConfirmed;
 
-  // TODO : Is this necessary
   bool mProtocolV2;
 };
 
diff --git a/toolkit/components/url-classifier/nsIUrlClassifierDBService.idl b/toolkit/components/url-classifier/nsIUrlClassifierDBService.idl
index aee1edfc023d..068621ba0895 100644
--- a/toolkit/components/url-classifier/nsIUrlClassifierDBService.idl
+++ b/toolkit/components/url-classifier/nsIUrlClassifierDBService.idl
@@ -7,11 +7,8 @@
 %{C++
 #include "Entries.h"
 #include "LookupCache.h"
-class nsUrlClassifierLookupResult;
 %}
 [ptr] native ResultArray(nsTArray<mozilla::safebrowsing::LookupResult>);
-[ptr] native CacheCompletionArray(nsTArray<mozilla::safebrowsing::CacheResult>);
-[ptr] native PrefixArray(mozilla::safebrowsing::PrefixArray);
 
 interface nsIUrlClassifierHashCompleter;
 interface nsIPrincipal;
diff --git a/toolkit/components/url-classifier/nsUrlClassifierDBService.h b/toolkit/components/url-classifier/nsUrlClassifierDBService.h
index 9d9671d9d8fa..39ceec0f7b66 100644
--- a/toolkit/components/url-classifier/nsUrlClassifierDBService.h
+++ b/toolkit/components/url-classifier/nsUrlClassifierDBService.h
@@ -146,10 +146,6 @@ private:
   // Close db connection and join the background thread if it exists.
   nsresult Shutdown();
 
-  // Check if the key is on a known-clean host.
-  nsresult CheckClean(const nsACString &lookupKey,
-                      bool *clean);
-
   nsresult ReadTablesFromPrefs();
 
   RefPtr<nsUrlClassifierDBServiceWorker> mWorker;