Are you talking about the grease that builds up on the zerk fittings ? I always wipe them first with a shop towel before greasing, then toss the rag.
I would never aim any kind of high pressure spray at a zerk. Seems like a great way to push water into the fitting. Those kind of sprays are for cleaning dirt and water soluble crud (SALT !) off the outside of a vehicle and the chassis - not to be aimed at zerks, electrical or fuel fittings from close range. And especially not at anything under the hood. Too much sensitive electronics under there these days.
Tim