I just bought 3 doz older canada shells (G&H) for 5 bucks a doz from a friend. He also through in 6 bladders to make them floaters. (eat your heart out) He is older and doesn't like to put them togeather. My question is, they are over 20 years old and the plastic is getting brittle, how can I fix that? Is there anything I can paint on the inside to help? Your thoughts would greatly be appreciated.