get a dremel tool,. preferrably one that plugs in to an outlet (I have been having TONS of problems with my lithium battry ones) and use that to GENTLY grind down the lettering. Gently is the key word. Take your time and do a good job.
And for the love of gawd don't hack at it with a rotary grinder like some people. Unless you WANT to have to bondo your gun!