C30TR owner here.
Clean with Simple Green and a cotton rag. Dark oil stained areas (from hands) appear black and are a buildup of human oils. Rub with CLEAN spot on rag and simple green. Typical spots are: grab rails, half bulkhead by chart table, counter surround in front of steps, and compression
post near head
If you have mold
or mildew on any teak use a mold/mildew remover instead of Simple Green because it prevents recurrence much better.
Do NOT use a scrub pad or abrasives.
Oil lightly. Reapply later if you must.
Do yourself a huge favor and invest the time in preparation to prevent oiling anything other than the teak. Aging oil on Fiberglas turns gummy, brown, attracts dirt and looks awful.
Any pieces attached with screws, unscrew and take off for oiling. That includes emptying the drawers and removing the surrounds. Sounds like a lot more work
, but you will be thankful later.
For teak that cannot be removed, Cut a flat edge from thin cardboard (eg 12 pack) to mask Fiberglas from oil.
out of the boat because you will probably spill or drip.