Can old rusty tools be cleaned and restored ?

Place in a 5 gal bucket and cover themwith diesel. Let them soak in the diesel for 2-3 days. Remove and let them dry, then use a drill powered cup brush to clean them up.

Evaporust works well

Grab a jug of rust remover from harbor freight, dump them in a bucket and leave for a day or 2. One of the few things I buy from harbor freight

Absolutely with Evaporust, Apple cider vinegar or electrolysis. Apple Cider could eat into the metal a little if you leave it a long time. Evaporust is great and non-toxic according to the package. I’ve never done electrolysis but it looks like it works great. It just takes some work to set up.

30% Muriatic acid and 70% water. Add the acid to the water... not water to the acid.

Let tools sit in it for about 20-25 minutes pull them out and if they need more time, do it for another 10 minutes.

Vinegar probably works pretty welll but will take longer.

We cleaned out some carbon steel HPU manifolds, nipples, plugs, etc... and they came out shiny.

After you finish with acid, vinegar, etc... whatever you use... a light coat of some type of oil will be needed. They will flash rust to some degree if not protected with something.