this has been a good post.
i too remove colonies,for the last 15 yrs.
everyones ideas are well founded,honey that comes from buildings can be poisoned they will not tell you or don't know! watch for areas of miss- shapened comb,old black hard w/ white powder.
i give my combs away to a nwco who uses it for animal bait,if suspect.
be prepared for a lot of work cleaning out the colony and many return trips to look at new bees that are there to clean up any spills.hard to explain this pattern to non bee keepers.
THERE ARE NO FREE-BEES.