When you are working with metal, whether casting, on the lathe, or by hand you will get slag and flash. This is a simple way to reclaim those leftovers back into useable metals.
Step 1: This Is Slag
Step 2: Collect All of the Slag Into a Pile
Step 3: Borax
Add about two tablespoons of anhydrous borax into the mix with the slag. This will both lower the melting temperature of impurities (such as iron), accumulate much of the slag in a molten glass-like substance.
Step 4: Get Your Torch
I prefer to use MAPP (a fuel gas based on a stabilized mixture of methylacetylene aka propane and propadiene) you can also use propane alone but it will take longer since propane burns less hot.
--- Warnings ---
Please only allow adults to handle or use torches or open flames.
Do not try to use these products in bright direct sunlight, the flame is blue and is not visible in some conditions.
Use in a well ventilated area and have a CO detector.
Follow all safety instructions on the bottle / MSDS.
Step 5: Caution
Step 6: Melt
Step 7: Shift It
Step 8: Finished
This method has worked well for me in the past. It usually yields 4-6 ounces out of a pound of slag.