[JohnFen]

I use food (including peanut butter) in cooking. I cook in the kitchen. Therefore peanut butter is a thing I use in the kitchen. Seems correct and proper to me.

The ambiguity as I see it is that the kitchen isn't the only place I use peanut butter. I've eaten it (which I think counts as "using") in other rooms. I've even made peanut-butter sandwiches (properly "using" it) in the living room before.