Question Why are keys sticking when I take them off to clean?

May 20, 2019
I have an old toshiba portege r930 ( I took one of the arrow keys off to clean when I noticed it felt like there was some dirt under it. when I put it back on it was stuck down, and when I tried to lift it up when I pressed it again it was still stuck down, and felt as if the membrane was too weak to push it up. The keyboard is a butterfly membrane with outward facing clips on the keys so you have to press it down hard to get it to clip on properly. even after multiple attempts to get it on just in case the dome was squished sideways it still refused to pop back up. The membrane and mechanism is clean as is the key itself. Has anyone experienced an issue like this before and if so can/how did you fix it?