08/16/2026
For my EM friends, you have probably heard of NAPTHA as a cleaner for metal parts on your game. NAPTHA is also Coleman Camp Fuel found at your hardware store.
Naphtha works very well for cleaning old grease and grime from EM mechanisms, but its vapors ignite very easily, so the biggest concern around a pinball machine is ignition from switches, relays, motors, soldering equipment, or the machine's power circuitry.
For EM work, I'd follow these rules:
Unplug the machine from the wall, not merely turn it off, before using naphtha inside it.
No ignition sources nearby: no smoking, soldering iron, heat gun, propane torch, space heater, pilot flame, or anything that can spark.
Never apply naphtha to a powered EM machine. Relay contacts, score-motor contacts and switches routinely produce small electrical arcs during operation.
Work with good ventilation and avoid deliberately breathing the vapors. If you're doing substantial cleaning, work outdoors or in a well-ventilated area when practical.
Use small quantities. Put some on a rag/swab rather than pouring or spraying it over the mechanism. Don't soak the wooden cabinet or mechanism panel.
Keep the original container closed and away from the work area except when dispensing it.
Allow cleaned parts to dry completely before reconnecting power.
Naphtha itself evaporates quickly, but don't assume an enclosed mechanism is vapor-free immediately.
Naphtha can remove oils and dry your skin, so nitrile gloves and safety glasses are sensible, particularly for extended cleaning.
Dispose of naphtha-soaked rags appropriately. Don't leave a pile of solvent-soaked rags in the pinball cabinet or shop.
Be cautious around paint, plastics, decals and printed markings. Test an inconspicuous area first.
