Xpantastic!

Hi, the master button is a bit difficult, it does not respond
correctly, i must push on the side to run it and the store button
sometimes sticks, sometimes not.

I thought buying some contact bomb but i don't know which one is good
and don't want to pollute the Xpander, do you know a good one?

Any other solutions will be appreciated, i would like to fix before
selling it, tanks.