I cleaned and polished my RT590 today. Been a while since I cleaned it, and the grates were really greasy with lots of buildup. Soap and hot water weren`t getting it done so I decided to use my Weber Genesis to blast off the grates with high heat. I let it ride up to 690 degrees for about 30 minutes or so and that did the job. Next time I`m just going to skip the soap and water. I hardly ever get my 590 past 275 and after a while it gets built up on there.