This is from a website in the United Kingdom (reads about how I remember learning copper grades in Texas). Putting the link to give them credit (but if that's not okay I'm copy/pasting the info here too :D
ASM-Recycling#2 Copper
This grade of copper can be identified by its somewhat dirty appearance. It should be comprised of miscellaneous unalloyed wire, pipe or solid metal that continues to have solder, paint or any kind of coating on it. Additionally, its minimum copper content should be 94-96%. In order to qualify for this grade, wire must be bare of insulation and be thinner than a 16th of an inch in diameter. The ends and fittings of #2 copper are generally accepted at dealerships, and oxidation of some wire, pipe or tubing is allowed as long as damage is not excessive.
#2 copper is the third most valuable grade available.
#1 Copper
#1 copper is the second most profitable type to trade in. To be classified as #1, the copper should be comprised of bus bars, clippings, commutator segments and wire of
at least 1/16th of an inch in diameter. It should also be clean in appearance,
unalloyed and uncoated.
The most valuable type of copper pipe – clean copper tubing – may qualify as #1 copper as long as it is free of fittings, insulation, paint, solder and other materials. In fact, most copper tubing and copper pipes can be of #1 grade providing they show few signs of corrosion and have their fittings removed. Trace amounts of oxidation on the tubing are generally acceptable.
Bare Bright Copper
Bare bright copper is by far the first among the types a scrap dealer would like to find. Also referred to as “bright & shiny copper,” it is the most valuable and high-paying grade around. It refers exclusively to bare, uncoated and unalloyed wire or cable – no thinner than 16 gauge in thickness – which is of #1 copper quality. Copper piping is not included within the classification.
As its name implies, samples must be stripped of insulation and other materials. Furthermore the metal must be free from any paint, impurities or signs of tarnishing. This includes any visible oxidation, and very negligible amounts of patina on the copper are allowable.
#2 Insulated Wire
#2 grade insulated copper consists of unalloyed wire – thinner than 16 gauge – which includes heavy, double or plastic insulation. The grade generally covers many common types of telecommunications wiring as well as electronics such as outlet and extension cords. Some coatings on the scrap, such as tin and nickel for example, as well as some degree of corrosion will also meet classification.
With its insulation removed, the wiring should look like #2 copper wire.
#1 Insulated Wire
#1 insulated wire consists of copper wire or cable which is clean, unalloyed, uncoated and untinned. It should also be plastic insulated, of 16 gauge thickness or larger, with all ends cut off. Though insulation does not need to be stripped, if it were the wire within should closely resemble ‘bright & shiny’ copper wire.