It's usually not a good idea to put anything into or on the piston assembly. The super heated gas coming into the gas cylinder will carbonize anything, turning it into a sticky, tar-like mess.
These systems are meant to be "run" dry of lube, solvent, or any other liquid.
Many people don't know this, and either lubricate the gas piston, or inadvertently allow solvent or lube to leak into the gas assembly during cleaning. This is why it's a good idea to clean the Carbine with the action upside down, so nothing gets down the gas port.
To disassemble the system:
Buy the GI-type gas piston nut tool.
Field strip the action, and lock the flats on the barrel into a WELL padded vise. BE CAREFUL not to damage the rails the op rod "box" run in. These can be dented or damaged ruining the barrel.
Use the piston nut wrench to unscrew the gas piston nut. The nut will "iron out" the staked area.
Once the nut is off, remove the piston, using a block of wood to tap the gas cylinder if necessary to get it out. DO NOT attempt to grab the piston with pliers or other tools. If it won't lift or tap out, soak with a good penetrating fluid over night.
Once the Assembly is apart, soak and scrub the nut and piston with solvent and a brass brush. NEVER scrape the piston with any steel tool. If the piston is scratched, it will foul worse, and is ruined.
A good item to clean the piston with is a "Lead-Away" cloth that removes carbon.
Clean the inside of the gas cylinder and it's threads with a brass brush, and use a brass or copper wire to VERY gently clean the gas port into the barrel.
Once everything is clean, DRY everything well, put a TINY amount of lube on the nut threads ONLY, drop the piston in and thread the nut on BY HAND, until tight.
Tighten the nut snuggly with the nut wrench, then re-stake into one of the open slots.
Unless necessary, don't try to re-stake into a used slot, use a new one.
If either the nut or piston looks scratched or damaged, replace the part. They're cheaper than a new barrel.