How to Clean Oil-based Old Stains from Clothes
This type of stains includes cooking grease, butter, paint, cosmetics, rust and other stains. They harden differently from water-based stains and thus require a different stain remover. In these instances, the cleaning solution first removes the oil layer and then the stain colour
Dry solvents are often the solution, but they are not for every fabric, as they can also damage it. For example, nail polish remover will efficiently remove nail polish stains, but it will damage the fibres of acetate fabric.
To remove old nail polish stains just blot it with the remover, then rinse with water and launder.
For oil paint, stains use paint solvent. Use the same process of first blotting the stain with the solvent and then rinse with water. Before laundering applying a stain remover product.
For food grease and cooking oil stains, you can use liquid dish detergent or shampoo. Work it into the stain, make it foamy, then rinse it with water. Additionally, you can give it a vinegar rinse.