Alternative to Mrs' Stewart's bluing?

Well, the active ingredient in the bluing that makes it all work is Prussian Blue. Mrs. Stewarts bluing is a colloidal solution of Prussian blue, which reacts with the ammonia and salt to form those fluffy white chrystals. Those by the way are known as Everitt’s salt, K2Fe2Fe3(CN)6. (Sorry, but I can't type the numbers as sub or upper script. The K2 should be down, the Fe 2 and Fe 3 should be raised). Anyway, it would be a major challenge to make the solution using Prussian Blue. If you aren't using it because you can't find it, maybe you can find one of the pet shampoos made to make white pets fur look whiter. Those will contain bluing as well- though if it works I can't say for sure. It's the same basic stuff, though, so it should.

Mrs Stewarts Bluing