Once roaches are this well established, you almost have to get an exterminator. Boric acid reduces the problom if you scatter it on the floor around the perimeter of each room. If there are pets or children, of course, you can't do this. I would suggest that you stop visiting your friend's roach motel until she fixes her problem; otherwise, her little friends will hitch a ride in your pockets and you'll be battling bugs at your own place. Meet her at Starbucks, for God's sake.