A very good rule to follow in beekeeping when obtaining used equipment is to assume it has had disease and handle it accordingly. Disassemble and Scorch the boxes as virus's and disease spores can hide for decades in the cracks. Cut out and melt all wax. It is best to replace the frames but at the very least dissaemble them, boil them for 1/2 hour in hot water, let dry fully, and then reassemble.