Some companies promote their products as "no prep." There's no such thing. Skip this process and your wood finish may fail due to adhesion problems caused by surface contaminants.
POWER PREP TUTORIAL
STEP 1. POWER PREP CLEAN WITH SOAPY WATER
Using soapy water made with a degreasing dish detergent, scrub away heavy, accumulated grease and grime with a green Scotch-Brite pad. Rinse away soapy water completely with clean water and terry cloth.
STEP 2. PREP CLEAN WITH 50/50 MIX
Scrub the surface again using a green Scotch-Brite pad and a 50/50 mix of denatured alcohol and water. Wipe dry with a clean cloth.
STEP 3. PREP SAND
Prep sand with a 220 sanding pad or 400-grit sandpaper. Wipe away all the dust with a damp cloth or towel. This provides an additional surface cleaning and prepares the surface to accept a new finish.
BE CAUTIOUS OF CONTAMINANTS
In addition to built-up dirt, oil and grime, dusting sprays containing silicone will also impact the appearance and adherence of a new finish. Silicone is almost impossible to remove. Oil soaps and wax can also cause adhesion failures.