Bubblers suck to clean. The angles always suck. The side of the bowl that doesn't have the carburetor has basically no access.

One good thing to do is use Epsom salts along with hot alcohol. The hot alcohol will soften the resin. If you can shake it with the Epsom salts inside, they will act as an abrasive and knock off some of the resin.

It might be a good thing to try in addition to the 420 cleaner.