admobadapter/src/main/java/com/clockbyte/admobadapter/AdmobFetcher.java
public synchronized void destroyAllAds() {
        mFetchingAdsCnt = 0;
        adMapAtIndex.clear();
        mPrefetchedAdList.clear();

        Log.i(TAG, "destroyAllAds adList " + adMapAtIndex.size() + " prefetched " +
                mPrefetchedAdList.size());

        super.destroyAllAds();
    }
public synchronized void destroyAllAds() {
        mFetchingAdsCnt = 0;
        adMapAtIndex.clear();
        mPrefetchedAdList.clear();

        Log.i(TAG, "destroyAllAds adList " + adMapAtIndex.size() + " prefetched " +
                mPrefetchedAdList.size());

        super.destroyAllAds();
    }
Destroys ads that have been fetched, that are still being fetched and removes all resource
references that this instance still has. This should only be called when the Activity that
is showing ads is closing, preferably from the {@link android.app.Activity#onDestroy()}.
</p>
The converse of this call is {@link #prefetchAds(Context)}.