Massive square bowl thing (possibly from Lakeland) Fill that with suds...put the grills in it...continue drinking...eventually remember they're in the tub...quick wash with one of those metal things Or alternatively just chuck them in the dishwasher
According to my daughter (who googled it, so it must be true), you cut a lemon in half, cover it with salt and clean it with that. No.1 son in law tried this and it definitely works, though he got fairly badly burned in the process. No idea is without its drawbacks...