Back in the 50's and 60's we had regular customers that plugs cleaned because their vehicles used so much oil that they fouled out in a hurry. I don't remember selling our Champion rig, but I'm not sure where its at either. I haven't owned a vehicle long enough in the last 30 years to have to change plugs. I feel that I'm money ahead by trading before a vehicles has 50,000 miles and plugs last longer than that. In fact I'm not even sure where the plugs are at on the last couple of 6L GMC's I've had. But I would have no problems using cleaned plugs in my old jalopies. In fact I would prefer a cleaned AC C45 over what is sold today.