baby back rib juice: what to do with it

so, i'm not a big rib cooker, but when i do, I season, wrap in foil and put on indirect heat at maybe 275-300 and cook for a couple hours then unwrap and finish on grill

my question is, there is so much juice liberated into the foil, what do you do with it:

throw it out, combine it into a sauce to finish cooking, throw it on top of the finished ribs at the end, other?

just seems to good to waste