Can One Use a Public Grill?
Shailah of the Week by Rabbi Zvi Nussbaum
Rabbinic Coordinator, Kosher Hotline Administrator for the Orthodox Union
Since a campground grill has been used to cook non-kosher foods (non-kosher meats and fish...), it may not be used unless it is properly kashered. The only way to kasher a grill top is with libun gamur (heating until the entire surface of the grill top rack becomes red hot). This can be accomplished by submerging the surface of the grill into burning charcoal. Even if the grill was used within the past 24 hours to cook non-kosher, and even if the grill had not been cleaned, it may still be kashered in this manner, since the intense heat will burn up all non-kosher residue and taste. There is no need to tovel the grill (immerse the grill in a mikvah), since it does not belong to you. It is owned by the park.
Instead of kashering the grill, an easier option is to bring along your own grill top and a couple of bricks. If the non-kosher grill can be lifted out of the way, the kosher grill may be put in its place, balanced on the bricks. If you purchase a new grill top, it must be toveled before it is used.
A third option is to double wrap your food with two layers of aluminum foil. Once properly wrapped, they may be placed directly on the non-kosher grill. In this case, it is better to clean the grill top first, or let the coals burn off the grease, before placing the double-wrapped food on top.