I can only assume that you have a Walther P22. I also had problems cleaning ALL of the residue out of my P22. Any pressurized can of cleaner will work just fine. Spray it down, let it sit for a while, spray it again, then maybe a can of air to thoroughly get all the cleaner out. Then oil it REALLY well and it should be just fine. And remember, toothbrushes and Q-Tips are your friend and should be in your cleaning kit.
AMAT VICTORIA CURAM