2,460. Orlah and Mixed Species of a Vineyard Used as Fuel
Maachalos Assuros 16:22
If an oven was heated using shells from orlah or from the mixed species of a vineyard as fuel, it must be allowed to cool before use; this is true of both a new and an old oven. One then re-heats the oven using a permitted form of fuel. If one cooked or baked in the oven before it cooled, it is prohibited to benefit from that food or bread because the forbidden fuel increased its value. If the fire was removed from the oven and one cooked or baked using only the residual heat, the food or bread is permitted because the prohibited fuel is no longer present.
Maachalos Assuros 16:23
One is not permitted to benefit from plates, cups, pots or bottles that were fired by a potter who used orlah shells as fuel since an item prohibited for benefit made them into pottery.