The best cleaner for your barbeque grill is an onion! The reason for this is it contains allicin which is an antimicrobial. To do this, heat your grill to high. Then peel and halve an onion. Skewer the onion with a long fork and rub the cut side over the grates. The grill should be clean after this. If any burnt-on food remains, squeeze some lemon juice on that, the acidity in it will break down any residue.