BBQ and Trays

I have 2 questions:

  1. how do you kosher a regular barbecue? It’s my understanding you scrub it and then turn it on high for a few minutes. Do you keep the grill open or closed when you kosher it?

  2. Can I double wrap a tray in tin foil and cook something on it? The food won’t come out good if I double wrap the food itself.

To kasher a bbq grill you clear the grill and then turn it on high for about 20 minutes while the cover is closed. This will burn out the grill.