HOW To Clean Oil Accidently Spilled in Washing Tub?

Call the washing machine manufacturer or the stain manufacturer. Each will have good advice.

Try soap or detergent or maybe a little bit of Dawn dish soap - you don't want too much suds but you need enough soap to deal with the oil - and then it should rinse away.

i'd hit it hard with a combo of dawn and white vinegar and scrub scrub scrub. then run it several times with hot water and plenty of detergent and old cleaning towels.
if that doesn't do it, you may be screwed. maybe call the manufacturer?
khairete
S.

How on earth? You need a professional to come out because that would get all over the mechanism and may ruin the machine

I would use Dawn dish soap or just regular laundry soap and clean it by hand first. Then run the wash empty or with stuff that would not be a loss if it got ruined with laundry detergent.

I would try Dawn or call the wood stain manufacturer.