The old advice on kerosene was to squirt a few drops on all gears and moving parts, run the machine and follow up with oil; but that was for sticky machines; not unreasonable amounts of grime. In extreme cases I have read of people soak the entire machine head in kerosene (motor and lighs taken off), with or with out disastrous results to the finish. I don't think I would risk it, even in the most horrible case. There is a youtube video on a guy using a steam cleaner in combination with degreasers to save a machine, but that's when there's literally an inch of dried up grease and grime internally. It turned out well.
Personally I have sorted to thin spray can oils of various kinds, they dissolve and flush out grime very well and are easy to get into difficult places with the thin straw they usually come with. They should in theory be more effective than kerosene, none of them are any less, but a bit more expensive if you end up using half a bottle. The beige 401 isn't shellac; I've had very good results with those velvety microfiber cloths wringed up in warm soapy water (on a beige 201K23), but that was the exterior. I don't think you need to worry about disinfectants; spend some time on it, use lot of cloths and when they get dirty take a clean one (if you are extra fuzzy, don't rinse it again in the soapy water, take a new cloth all the time). Bacteria don't like dry clean surfaces, I'm sure your 401 will be improved by the US health department
