I sort my aluminum into several different boxes, the best being: Copper/Al $1.74lb, Extruded Al $.70lb, Clip $.66lb, painted $.57, Cast $.53, Old $.53
Now the prices will vary depending on region and you scrap yards, but it gives you a break down of what is worth more. There are a few more type like Al Wheels that pay higher then extruded, but in our business we don't deal much with them. Then you have all your dirty Al's but they pay so little its worth cleaning them up.
Aluminum;
Wheels: must be made of aluminum. Steel rims are considered short steel or alloy free. The wheel weights and valve stems must be removed to receive full purchase value. Wheels with plastic coating or chrome plate are purchased as dirty wheels even if the weights and valve stems have been removed.
Old sheet: any type of aluminum sheet with small amounts of contamination such as screws, staples, light tar, caulk, etc. Non-returnable pop cans are also purchased as old sheet as well as other cans such as aluminum cat food cans. Pontoons are purchased as old sheet but they must have a hole cut in them so we can see that there is no foam, water, etc. inside.
Painted aluminum: siding, soffit, facia and other similar materials. Most sheet type aluminums that have been factory painted (not hand painted) that are completely free of contaminants.
Cast aluminum: grill tops and clean aluminum pistons are good examples. Must be completely free of contamination.
Clip aluminum: clean and shiny aluminum like lawn chair frames. Must be completely free of contamination.
Extruded aluminum: window and door frames. Material has been run through an "extruder" so it is molded, not folded. Must be completely free of contamination. Unclean extruded is allowed to have small amounts of contamination.