I had some rust on my donor, I too bought lots of things, including a sandblaster to hook up to my compressor. Bought fine sand initially, which gummed up to the gun. Then replaced the gun and got proper blast media. Makes a big mess, I did it outside, needs sweeping/hoovering.
I had very good results with a homemade electrolysis setup; big bucket (initially tin as it’s what I had, later upgraded to €4 plastic Aldi laundry hamper), strips of thick, cleaned steel for the anodes, and an old-fashioned (not smart) 12V power supply. Coat hanger for cathode, Persil for the conduction medium. Leave for 24 hours or more.