@ibstubro
For future reference, there is an alternative to just dumping a garment with a stain that just won’t come out no matter what.
Are you familiar with a product called Heat N Bond?
It’s basically a very thin layer of permanent washable clothing glue sandwiched between two pieces of paper.
This enables one to use an iron to affix one side of it to a piece of cloth. It can be a solid color which you will cut into a shape (such as a star) or a pattern containing artwork you like (trees, hunting dogs, whatever) that you can cut around the outline of. This basically makes a custom designed decorative patch.
After you get the material ironed on and cut to size, simply peel off the other sheet of paper, place glue side down and iron for the time specified.
You can also place a few more matching design over places where there aren’t any grease just to even out the design or leave as is.
There’s your new custom designed shirt without grease stain and totally unique.
You can also use Heat N Bond in place of sewing (like raising a hem or covering a rip or tear.)