And always charged a small rental fee for all your serving pieces, if they prefer to have someone else attend the buffet, get an adequate deposit to cover all you materials they are renting, they get a percentage back once it has been returned, undamaged.
ie. I had a bride a few years ago, who rented chair covers, linens, chair sashes. and other item from me, as well as lighting. She signed my contract stating that damaged or missing items would be charged in full. Well, I had 3 strands of lights that were completely severed before the plug, 4 missing sashes, and a wax stained runner, not to mention 2 missing chair covers. I got $172 from her in damages/missing items.
So, if one apothecary jar costs $40, and you rent it for $10, get a deposit on it for $25-30 more if you won't be present, you keep the $10 for the rental fee, and they get back the $25-30 for the deposit if the glass is not chipped, cracked or altogether missing.
I also had a checklist my customers would have to sign that they were receiving items in good condition, they checked everything they were renting, and it was checked back in upon return.
Also, do a search online to some of these rental places, you would be shocked at some of the prices they get for items.