While it may be comfortable to apply fingernail polish when sitting on a mattress, you're also more likely to spill it as you shift positions. However, you can remove most fingernail polish stains from mattresses with the right combination of tools and techniques.
Blot the stain with a clean white cloth to remove excess liquid.
Place a few drops of fingernail polish remover containing acetone directly onto the stain with an eye dropper. Blot the area immediately with a clean area of the cloth.
Add a few drops of dry cleaning solvent onto the polish stain using the eye dropper. Blot immediately with the white cloth.
Repeat step three if the stain remains.
Dab the area with a sponge dampened in cold water. Blot dry once more.