2015 mac, i cracked my W key in half, then *lost* half, need help

Has anyone here cracked a Mac keyboard cap in half, lost half of it, then successfully juryrigged a replacement? I was doing okay peeling drug bottle labels off and using that to keep the to halves of the key in place, but I snagged the loose half of the cap with some gesture or other and it went flying into the abyss. Now the sticker fix is pretty bad; doesn’t depress the key enough to register, sticker comes off sooner, etc. I’m getting soft in the head and my facility for temporary repairs is being completely blotto. I do have a dead-battery Mac (those get an “LC” rating on the Endangered Species list), are the key caps clipped on only or also glued on?

I put another key I don’t use on it and it fit great; I do want to put the temporary fix key cap back on the “[” key and find something other than a non-spare key cap to replace the one I split with, but it’s less dire now :D. Looking forward to hearing how other frequent-W-flyers of the Mac variety have solved the problem of the cracked key cap.