Rib racks in comps; Do you foil, etc?

A follow on question from Dan's thread:

If you do use rib racks in comps, do you foil?

If so, do you put any butter, brown sugar, etc... in the foil before wrapping them up? For my thought, I can't see how it would work, but, inquiring minds want to know. :mrgreen:

Thanks.

wallace