one idea would be casting new ones. it isnt as hard as it sounds, you can buy kits for this sort of thing. prety much you get a clay of sorts push the items into the clay and remove the item from the clay cast an epoxy style resin into them. that is the basic way, you can buy the kits on the net for $30-$50. you can also buy another kit, if the items are broken where you make a silicone rubber molds, here is a link to a how to. ive done plastics and composites as a job for years, this sort of thing isnt out of the limits of an average person on small scale like this, i was before finding a new wcs ball going to make a mold and cast a new one. however i found one, so didnt bother, if you have no luck this could be a very usfull thing for making new inserts cheaply
http://www.wonderhowto.com/how-to-make-simple-one-piece-silicone-rubber-molds-165756/ps if wondering about different colors, you can buy tinters for the casting material
