Clean out the cylinder and the piston really good. Most pistons are chromed on the head but the face of the piston will blacken and you may never get back to shiny chrome there. If you made a decision to shoot corrosive, like Yugo ammo, you better do this every time. No lubrication or oil should be left in the cylinder or on the piston. Not needed and will just attract crud to stick and make gooey mess. Or maybe largely just evaporate if the gun runs hot there. Lot of surplus ammo is pretty dirty so it tends to build up before too long.
Your gun is like your nose, it is just wrong for someone else to pick it for you!