When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
If carpeting has imbedded oil/grease stains on it, try rubbing some hand cleaner [the sugar beet stuff] into the pile where the grease is located. The carpet needs to be DRY [no water added] and then the cleaner needs to be rubbed in really well...a soft plastic bristle brush might help get it down in the nap. After working it in, the color should change as it loosens the grease. When done, rinse it out with warm water, then wash the carpet as you usually would with soap, detergent, or other carpet cleaner.
Finally got to the point with my interior project when it was time to dye the vinyl parts. I did purchase a paint sprayer and tested that method on a piece that I was not going to reinstall. I also tested a brush-on method using a shoe polish applicator.
I liked the latter method because it does not leave a "layer" of dye on the surface, and I can get even application of dye also on the "hard to reach" areas.