Cambro. They are embossed with the graduations. They are made of food grade plastic. They are made for commercial kitchens and will outlast you. You can get them at any restaurant supply store
My understanding of the washing soda is to raise the pH for saponification of fats and other non-polar compounds to dissolve in water. Saponification works best with more basic solutions which is why lye is used in soap making. By reducing the pH by adding vinegar you're neutralizing the washing soda to a degree because it reacts to create water with carbon dioxide and sodium acetate which overall makes a less effective detergent
I don't think you'll find it. Mayonnaise has a mechanism of lipid oxidation catalysed by iron ions present in egg yolks. Most mass produced mayonnaise contains EDTA to chelate metal ions and slow down lipid peroxidation. Lipid oxidation is also known as rancidity.
You can test this yourself by leaving a metal utensil in some mayo for a couple hours. It should turn black from a redox reaction
Yours doesn't roll over?