1. Line the bottom of the bathtub with two old towels. This is an important step -- to prevent the grill from scratching the tub or your favorite large tub, then lay the grill flat on the towel. Add hot water to the tub and let it soak the grill.
2. Add half a cup of dishwashing liquid and stir gently to allow the liquid to spread. If it's powder, stir it to dissolve it completely. Leave it to sit, soaking the grill for hours or even overnight.
3. When the dirt on the grill comes loose after soaking, it's fairly easy to scrub with a brush or sponge.
4. After scrubbing, rinse thoroughly with clean water, and wipe dry air, can be used.