Mickey2

I would not use line seed oil on the paint unless it's in very bad and damanged condition. I've seen the thread on how to revive a machine in very bad condition and the result is very impressive. I would however start gently to clean with sewing machine oil or microfiber cloths wringed up in lukewarm water, just slightly damp, like straight from the spin cycle in the washing machine. Shellac can take this treatment with out being affected, the exception is if it's very flaky and damaged to begin with. Dirt is luckily not that bad or worrysome.

Edible oils, like plant oils and waxes oxidates, it makes the shellac deteriorate faster decades down the road. To prevent this oxidation it's suppose to be better to use resin based car wax, and mineral based furniture wax made for antique polishes. This is advice from a conservationalist point if view, with the idea that these machines should hopefuly be in as good or better condition when we hand them over to the next owner as we recieve them our selves. It's amazing how long these cast iron machines with hardened steel gears can last.