You see something similar on metalworking videos: "I just used this scrap piece of steel/brass/copper/aluminum I had laying around". Conveniently leaving out the fact that it's hundreds of dollars of raw material.
To be fair the scrapbin in a Metall workshop thats been running for some time is usually pretty full and has some nice pieces.
In production it's often the case that you have to be carefull not to keep to much junk.
(Source: professional metallworker)