Gum Ball Machine Maintenance. Grandpa to the rescue. We've had this since my sons were little and now my grandkids get to use it. That was until yesterday, when the coin mechanism got jammed. So, I took it apart and much to my dismay a spring came flying out of it. I hate it when that happens! I wish I'd taken before pics! It took me 10 minutes to figure how that spring and dog went back into the mechanism. Anyway, I adjusted this and that, put a little mineral oil here and there, and it's working again. Tomorrow the kiddos will be asking for more pennies to operate the "M&M Machine". Now I have a picture in case it needs disassembling again! By the way, I had 4 knives on my person as all this was accomplished! I also ate too many M&Ms as I was testing the reassembled unit!