Not sure I always got mine at Walmart or Lowes and when I could not find them I took heavy duty foil and use a big sheet and filled in the bucket until Walmart or Lowes had them in stock.
A friend of mine told me about using a pickle jar and put in the foil lined bucket to catch the grease. After the cook just put the lid on, works great, you just have to remember to take the lid off when you use the grill again. Keeps the rodents away from the patio.