How to get oil/grease stains out of bath tub?

i work at a factory and have oil/grease stains in my bathtub. i've tried usind degreasers, magic erasers, and bleach. none of these will get it out. any suggestions would be niceHow to get oil/grease stains out of bath tub?
Vinegar or lemon juice- the acidity cuts through grease.How to get oil/grease stains out of bath tub?
dawn diswashing detergent with grease busters.
why were people cooking bacon in your b tub
TSP is an industrial strength cleaner sold at home centers, it if doesn't remove it, it isn't grease.
This question was asked this morning.. Maybe it would be a good idea to try some of things instead of just asking the question again? Get some cheap dishwasher detergent and apply a thin layer in the bath tub let it sit for 10-30 min. Rinse with hot water... Also, soft scrub works if the grease/dirt is really stubborn use a scotch brite non scratch brillo... NOT a brillo pad that's made of aluminum... If that doesn't work.. Get a new tub.....

maybelline express