Glad to see the thread gets the point in the end. We NEVER reused glass jars when packing honey as the risk was just so much greater than fresh glass of known origin.
This came to a head with glass shards being found in jars of honey. The jar looked perfect, but the guy involved did indeed take jars back from customers and washed and dried them with great care. he was quite proud of the eco friendliness (before such a term was even used) and the money saved (though in a business setting it is usually more expensive to clean and sterilise than buy new with honey jars). His product was excellent, looked great, and sold well.
Then there was a claim from a consumer with a cut mouth. Then after a while another, Local EHO investigates and finds out about the reused glass. I was shown the problem and it is a real one too.
When you wash jars for reuse in a small scale setting it is common for them to ***** against eachother. The jars can look perfect, but small introduced defects in the thread area are very hard to spot. Small edges and pieces of thread pattern sometimes then come detached and can end up in the honey. Sorry for those who think it an unreasonable intrusion, but it DOES happen, and these are increasingly litigious times.
The point also made about you never know what the person returning the glass may have had in it is oh so true. If they have had jam in the jar (and I have seen people put anything from old cooking oil to urine in them, wash them and think them good as new) then no matter how clean you wash it it gives taint to the next think in there. An extreme example is to wash out a jar that has had any product with a smell to it, say rasp jam, then fill it with dry white sugar ad put the lid on. Go back after a week and open it. You will smell the jam.