Sorting aluminum scrap by type and cleanliness can increase its value by 20 to 40 percent compared to selling it as a mixed load. The difference between dirty, unsorted aluminum and clean, properly graded material is dramatic: irony or contaminated aluminum fetches just $0.05 to $0.15 per pound, while clean aluminum extrusions sell for around $1.10 per pound and premium aluminum wire reaches $1.15 per pound. The sorting process starts with separating aluminum from other metals, then moves to distinguishing between aluminum types.
Separating Aluminum From Other Metals
The first step is removing any ferrous metals (steel, iron) from your scrap pile. A simple magnet does this job. Run a strong magnet over or through your material, and anything it sticks to isn’t aluminum. This is the same principle industrial recyclers use: mixed waste streams pass through magnets first to pull out all ferrous metals before any further sorting happens.
Once the steel and iron are gone, you still need to separate aluminum from other non-ferrous metals like copper, brass, and zinc. Color is your best friend here. Aluminum is silvery-gray and lightweight. Copper is distinctly reddish-brown, brass is yellow-gold, and zinc is darker gray and noticeably heavier than aluminum for the same size piece. Picking up two similar-sized pieces and comparing their weight is one of the quickest identification tricks. Aluminum feels surprisingly light.
Telling Cast Aluminum From Wrought
This is the sorting step that matters most for your payout. Cast and wrought aluminum have different alloy compositions, different recycling pathways, and different prices. Cast aluminum typically brings around $0.50 per pound, while clean wrought extrusions sell for roughly double that.
Cast aluminum is formed by pouring molten metal into a mold. You’ll recognize it by its rougher, slightly grainy surface texture, sometimes showing the pattern of a sand mold or small surface imperfections. Cast parts tend to be complex, three-dimensional shapes: engine blocks, transmission housings, lawnmower decks, cookware, and power tool housings. They’re generally thicker and heavier-walled than wrought pieces.
Wrought aluminum (which includes extruded and rolled forms) looks and feels different. Extruded aluminum has a smoother surface with a uniform cross-section along its entire length. Look for faint parallel lines running lengthwise, called die lines, left behind by the manufacturing process. Common examples include window frames, door frames, aluminum pipes and tubes, L-shaped angles, U-channels, and decorative trim. Rolled aluminum shows up as sheet metal, siding, gutters, and cans. Clean aluminum siding and gutters average about $0.67 per pound.
Sorting by Cleanliness and Grade
Contamination is the single biggest factor that kills scrap value. Materials with attached steel, plastic, rubber, or insulation can lose 80 percent or more of their value. Before you sell, strip off any non-aluminum attachments: screws, bolts, rubber gaskets, plastic end caps, insulation, and paint where practical.
Industry grading standards set by the Recycled Materials Association (formerly ISRI) define what buyers expect. Their top aluminum grades require 99 percent or higher aluminum content, free of iron, copper, insulation, and other non-metallic items. Electrical conductor grades (like wire made from 1350 or 1050 alloy) require 99.45 percent aluminum content. You don’t need to hit these exact numbers at home, but understanding that buyers pay for purity helps you see why spending time cleaning and separating your scrap is worth it.
A practical sorting system for most small-scale recyclers looks like this:
- Clean extrusions: Window frames, door frames, and structural shapes with no paint, screws, or attachments
- Clean wire and cable: Bare aluminum wire stripped of insulation
- Aluminum siding and gutters: Often painted but otherwise clean sheet aluminum
- Cast aluminum: Engine parts, housings, cookware
- Dirty or irony aluminum: Anything with steel bolts, rubber, plastic, or heavy contamination you can’t easily remove
Tools That Help With Identification
For most hobbyists and small-scale scrappers, your eyes, hands, and a magnet are enough. Weight, color, surface texture, and shape will correctly sort the vast majority of aluminum scrap. A kitchen scale helps when you’re comparing similar-looking pieces, since aluminum is roughly one-third the weight of steel or copper for the same volume.
If you’re sorting at higher volumes or need to identify specific alloy series (like telling 6061 from 7075), handheld X-ray fluorescence (XRF) analyzers are the standard tool in the scrap industry. These handheld devices can identify aluminum and dozens of other alloy bases, including magnesium, titanium, nickel, copper, and zinc, in seconds. They’re accurate enough for commercial grading. The downside is cost: handheld XRF guns typically run several thousand dollars, making them practical mainly for professional scrap yards rather than casual recyclers.
A cheaper alternative for occasional use is a spark test. Grinding aluminum on a bench grinder produces small, white sparks that extinguish quickly, distinctly different from the bright orange showers thrown by steel. This won’t tell you which aluminum alloy you have, but it confirms the metal is aluminum.
How Industrial Facilities Sort at Scale
Understanding how large recycling operations sort can help you appreciate what’s happening to your scrap after you sell it, and why cleaner loads command better prices.
Eddy current separators are the workhorse of industrial aluminum recovery. These machines use a rapidly rotating magnetic field to induce electrical currents inside conductive metals. Those currents create their own magnetic field, which repels the aluminum pieces off a conveyor belt and into a separate collection bin while non-metals fall straight down. A single pass through a high-force eddy current separator can produce aluminum concentrate with 85 percent purity while recovering over 90 percent of the aluminum in the feed stream.
For finer sorting between aluminum alloy types, facilities use sensor-based systems. Laser-Induced Breakdown Spectroscopy (LIBS) fires a laser at each piece of scrap, creating a tiny flash of plasma on the surface. The light from that plasma reveals the exact chemical composition, allowing automated systems to sort by alloy at high speed. LIBS offers short measurement times and high sensitivity. X-ray fluorescence works similarly but uses X-rays instead of lasers to analyze composition. Both technologies can distinguish wrought from cast aluminum and even separate specific alloy grades on a fast-moving conveyor line.
Newer approaches use differences in electrical conductivity to sort alloys. Since wrought and cast aluminum conduct electricity differently, systems that measure conductivity across multiple frequencies can classify pieces without needing to analyze their chemical makeup. This technology works well for the critical wrought-versus-cast separation that determines so much of the scrap’s value.
Getting the Best Price for Your Sorted Scrap
Call multiple scrap yards before you sell. Prices vary significantly between buyers and regions. When you bring in pre-sorted, clean loads separated into distinct categories, you’ll typically be paid the going rate for each grade rather than a blended price that averages everything down to the dirtiest material in the pile.
Keep your sorted categories physically separate during collection and transport. Mixing clean extrusions with cast aluminum in the same bin forces the buyer to either re-sort it or pay you the lower cast price for everything. Bringing clean aluminum wire separate from extrusions, separate from cast, and separate from contaminated material gives you leverage to negotiate each pile individually. The time you spend sorting at home directly translates to a higher per-pound payout at the yard.