Chocolate

Question

Rabbi, I know you've probably answered this questions so many times, but I just want to be sure: I called up a chocolate factory to see if one of their chocolates has milk. They told me no, but that it can be made in the same equipment as milk chocolate and therefore there may be some milk residue. So they can't guarantee that this non-milk chocolate does not absorb any milk. I don't think they clean the equipment. Is there any way that this may be a problem? What if they don't wait 24 hours before producing the non-milk chocolate after having produced chocolate with milk? What if milk residue is accumulated by the non-milk chocolate and it becomes more than 1/60th of it? Just want to be sure that it's 100% ok. Thank you for your time and patience.