The issue then becomes "plausible deniability". You cannot claim you didn't know they were stolen if the serial number is ground off. So whomever grind the nu

The issue then becomes "plausible deniability". You cannot claim you didn't know they were stolen if the serial number is ground off. So whomever grind the numbers off, may as well cut it open and extract the metals. It puts a major obstacle in the supply chain.