Can Milk Paint be applied to an existing Glossy surface?

Glossy surfaces have the most risk of poor adhesion.

1. Clean your project with a Scotch Brite pad and a 50/50 mix of denatured alcohol and alcohol. Do not use mineral spirits with a water based product. SECOND, sand with 150 or 180 grit. Sanding is critical to the success of every finishing project as it further cleans the surface and opens up the grain to improve the adhesion of the new paint or finish.
2. TEST your procedure on the inside of a door first, letting the paint cure for 14 days. Then test the finish by duplicating normal wear and tear: washing, scrubbing, scratching, etc to see if the finish bonds to the surface.
3. The cabinets may need to be de-glossed with a de-glosser solvent available at any paint store.