Hi, I'm new to the community and very new to Vintage drums. I have a question for anyone who may be able to help me.

I just bought my second vintage kit. A blue sparkle unknown kit, which seems to be in very good condition. My problem is, the former owner didn't change the heads very often. For About 25 years, the toms have had the same heads. And upon removing the heads, I noticed that pulling them off wasn't that easy. It's almost like the shells have expanded a few centimeters bigger than their regular sizes of 12", 13" and 16". I finally got them off, and I decided to see if new heads would fit. The new heads could barely fit. Is there a way I can fix this? Thanks alot for checking out my question.