Going back to soda crystals, as used instead of bicarb for the silver soaking tip, someone said that they would not fancy putting their hands in a solution of it? I've used it for various things and never had a problem.
Just the other evening there was a particularly grim looking pyrex dish amongst the washing up. It had contained Mr P's special macaroni cheese, which we had for supper then bunged the same dish in the oven the next day to heat up the remainder for lunch, so the hard residue was twice baked!
I ran some very hot water, a squirt of washing up liquid and a couple of tablespoons of soda crystals and left it to soak for 10 minutes. Came up brilliantly, no scouring or scrubbing!
It works out much cheaper than things like Fairy Power Spray.
Also am I right in thinking that the bath salts many of us used years ago were just scented and coloured soda crystals anyway?