the pieces that have lost their grip.
I won an auction on ebay for a few sets(sheriffs lock-up, bandits secret hideout, renegade runner, broadsides brig, and wavemaster) for a great price of $55. A lot of the pieces from the 2 pirate sets are like this. I don't get how this happens as I have bricks from the mid 80s that are still as grippy as ever but there you go.