Examine the Stain

• Although even very fresh stains can be painted over, the best practice is to make sure the stain is dry before painting over it. If the stain is still wet, it may mix with the paint and show through when the paint dries. Gently pressing a white paper towel against the stain is a good way to test for dryness. If the paper towel absorbs any of the stain, it is not yet ready for paint.
  
  

Prepare the Surface

• Not all surface preparation is the same. If the stain is on a smooth surface that can be sanded, a light sanding with a fine-grit sandpaper can help lessen the stain and provide a cleaner surface for paint application. If the stain is on textured drywall or another surface that is not as simple to sand, this step may be skipped. If any sanding is performed, be sure to thoroughly remove any dust generated by this process from the surface before continuing.
  
  Oil-based primer is extremely helpful in covering stains. Two coats of primer are best, but even one can be very effective in sealing the stain. If primer is not used, the stain may eventually bleed through the paint, even after several coats of paint have been applied.
  
  

Paint the Surface

• If primer has been applied, it should be allowed to dry for several hours at room temperature. Using a roller appropriate for the surface (smooth, semi-smooth or rough), apply a coat of paint over the stain, blending it into the surrounding areas. It is better to do several thin coats of paint than one very thick coat. Thick coats of paint tend to chip more easily and often appear bubbly or runny.
  
  

Repeat as Needed

• After the paint dries, inspect the surface. Use a light to carefully go over the entire stained area. If any stain still shows through the paint, apply another coat of primer, allow it to dry, then apply another coat of paint. This may be necessary for very fresh stains, even if they were dry when this process was started.