For HDDs, "refurbished" probably means FORMAT'ed.
In the old days, it sometimes meant a LOW-level format.
SSTOR ("Speed-Store") and SPINRITE (Gibson's) "REFURBISHED"
drives.
For other things, it probably means plug it in and see if the power
indicator comes on.
Maybe even wipe it off with a damp rag.
Maybe some isopropanol to scrub off the "NFG" that somebody had written on
it with a sharpie.
OR, "refurbish" gets the FRY's definition. Just sell it again. If it
comes back, substitute another until the customer gets one that works.
Put the bad one back on the shelf, and keep selling it until some customer
doesn't go to the effort of bringing it back.
Q: what does "FURBISH" mean?