Powder coating question about how to mask letters off most efficiently when painting?

I have started powder coating and it works really well. I want to be able to paint valve covers, but want to keep the raised letters on the valve covers unpainted because they are already polished. I want to do this with multiple valve covers and it seems very time consuming to sit and mask of letter of letter. Does anyone know of an easier way to get a good result? With the letters being raised is their a better way to remove the powder coating after or before paint is cured? I am open to any suggestions, I have thought of a few ways I could do it, but am not sure of the easiest, fastest and most efficient way. If anyone has any ideas I would appreaciate it, ThanksPowder coating question about how to mask letters off most efficiently when painting?
smear grease on the top of the letters. The stuff will not stick to the the grease.