@Alexandra2041 Sadly people now expect a barbecue to be spotlessly clean when they arrive. The far better cleaning method for charcoal barbecues is to not clean them after use so the grill is protected. Then when the barbecue is lit the next time any grease/food residue burns off and is removed with a wire brush before cooking.
Given that this is too hard to explain to guests we don't provide a barbecue but will lend our weber to them if they 1) ask and 2) are willing to agree to our cleaning routine.