I assume they didn't put them inside the cylinder head, only on the cooling fins. If they put anything inside, they might have scratched the cylinder and or piston which could have ruined it. You should be very careful handing the piston cylinder and head. If you must - carefully wash them with dish soap and warm water. Rinse them well and dry them carefully. Don't use anything that would be abrasive at all. After washing them I sometime rinse them with a little rubbing alcohol to dry them better, then I apply a little bit of oil to aid in assembly.