#1 copper can be copper such as clean copper pipe with no other contaminates on the copper pipe.
#1 copper is also copper wire that is 14 gauge thick or thicker. An example of #1 copper wire would be the Romex copper wire that is in houses.
If you take that Romex Wire and strip the insulation off of it then it would be classified as clean #1 copper.
#2 copper would be any copper wire that is thinner than 14 gauge wire would be for example copper wire that you remove from electrical cords.
It can also be contaminated copper pipes depending on your scrap yard.