Hopefully you shouldn't have to do anything to it except rinse it off with really hot water and dry it (the heat will help evaporate any water that is left behind). I do alot with cast iron Dutch Ovens and the last "pre-seasoned" one that I got actually had a thin coat of wax on it. Scrape a finger or thumbnail on the grate and if it comes away with a waxy buildup on the nail, put the cast iron in the Performer and bring up the heat (300-350°) to melt the wax off the grate. Let it cool off and give it a quick wash with hot soapy water (DON'T LET IT SOAK IN THE SOAPY WATER), rinse it well with hot water and dry it off. Before using for the first time, give the grate a very light coating of vegetable oil and build your fire. Do this 2-3 times during the year to build on the original seasoning.
YMMV
