No Oven Cleaner, either!

Turpentine or Mineral Spirits, on an old under-shirt rag, will clean off old grease, dirt, mold and grime. It may also soften up old Finish (varnish/shellac/?).

I have stripped stubborn varnish and Birchwood Casey "Lin-Speed" coatings with a small 1x2 inch square pad of green 'Scotch-Brite', saturated with Formby's stripper, following the grain & using very light pressure.

Change 'pads' as they load up with junk. Follow-up with several hand-rubbed coats of 50/50 mix of Linseed Oil & Turpentine.

I like a final coat and 'rag-buff' of Howard's "Wax & Feed".

Note some will disagree and say I'm a "Barbarian".

Approach has a lot to do with the 'Wood Situation' you start with.

(Here's photos of an abused 'trapdoor' I cleaned up):

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