Duct tape or Velcro. Use both just depends.

 

I use hot glue to attach accessories to skeletons. peels away easy with no damage to skeletons.

 

Velcro Sticky Back Squares are your friend.

https://www.lowes.com/pd/VELCRO-12-Pack-0-875-in-Black-Fastener/3020010

 

never used it on a prop but there's removable seasonal weather sealant (caulk) that just peels off when it's dry. similar to the stuff they use to hold credit cards to the letter when you get them in the mail. it's made for temporarily sealing around windows and stuff during the winter. It can get gooey again after a long time, like i mean months, so if you go that route, it;s best to peel it off right away when you are done.