But if someone uses those clean parts and has an accident, you could be held liable. Happened to someone I knew long time ago. He serviced their bike, cleaned and lubed etc. A little while later the freewheel locked up, sending the rider into a crash, smashing their knee cap against the kerb edge. Accident investigation, revealed the locked up freewheel and the recent service. Court case followed and found the fault lay with the servicing. Thousands with many noughts on the end was the compensation ruling.