Step 2. Cooking Grids and Grates: 
Grids are most efficiently and easily cleaned on an ongoing basis by simply pre-heating the grill on high for 10 minutes before each use, and then scrubbing with a brass bristle brush (fig. 2). Carefully wipe grids with a paper towel before use. For a thorough cleaning remove and inspect the Cooking Grid/Grids. (make sure gas supply is shut off.) Most grills have either chrome or porcelain coated cooking grids. If the chrome grid is Not excessively rusted, soak in a hot soapy water solution to loosen accumulated grease, (a degreaser may also be used) then scrub with a steel wool pad or a stiff nylon pad (fig. 3). Rinse thoroughly and lightly coat with cooking oil before use.
If you find broken welds, or cannot adequately remove rust, you may opt to replace the grid. Porcelain grids may be cleaned in the same manner. After cleaning, check for excessively chipped and missing porcelain. Again, you should replace grids that are badly deteriorated.
Next, remove the rock and rock grate they rest on (fig. 4). If your grill was supplied with Lava Rock (fig. 5), and they have Not been changed in the last season or two, it is usually best to simply replace them. Lava Rock absorbs grease over time and can cause flare ups if they become saturated with grease drippings. Lava Rock is relatively inexpensive, but make sure you purchase a good quality rock that doesn't fall through the Rock Grate opening. Some grills may be supplied with a better quality rock, usually round or pillow shaped (fig. 6). 
This usually lasts longer than Lava Rock and does Not absorb grease as readily. Lightly brush residue off with a wire brush (fig. 7), and put them aside until reassembly. If many pieces are broken or crumble, replace with a good quality Pumice or Ceramic Rock. 
An easy way to clean this type of rock on an ongoing basis is to periodically turn them upside down and cook on the opposite side (fig. 8). The heat from the burner will gradually clean the under side of the rock. When it comes time to reinstall the rock, make sure it is distributed evenly across the Rock Grate surface. This will help the grill cook at an overall even temperature. When replacing uniformly shaped ceramic or pumice rock, arrange the rock to have a minimum amount of space between them (fig 9). 
This will reduce the amount of grease dripping directly onto the burner flame and help reduce flare-ups. Flare-ups many times are caused by cooking on too high a heat setting. Finally, inspect the Rock Grates. This component is subject to very high temperatures and will weaken and deteriorate over time. Knock off loose rust and scale with a wire brush. 
If grate is very thin, or sags excessively (fig. 10), replace with a new grate sized to your model, otherwise this grate can go back into the grill for further service. There is No need to paint this part.
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