I've a friend whose accordion (yes I know I goofed with the spelling in the thread title) has two keys that catch against each other. I suspect that damp is the culprit and the wood of the key has warped. Is there any way to repair this damage that is economically viable on a box bought for £60? Only way I could see was to file the sides of the two keys that are catching on each other to get a gap back, but this isn't going to look very pretty.

Any ideas from the experts here?

Scott