I was recently given a top-handle toolbox filled with many wrenches and sockets, some punches, screwdrivers, pliers, a few taps, dies, and drills, and other stuff, I'd say, about 15-20 lbs of tools. I got a 5 gal bucket, some 'cleaning vinegar,' and I left the tools in there for about 3 days.
When they went into the bucket, they looked like yours. When I rinsed them off 3 days later, nearly any rust was gone. There was a dirty-brown foamy, slick layer of that which had migrated-off the tools, some heavier stuff lying on the bottom, and other in the foamy layer.
I used a respirator and wire-wheeled all the tools that were worth keeping. You don't want to breathe the cadmium plating, a serious carcinogen!
When done, the seriously-rusted tools were clean down to the pits. I don't think any tools in the wrenches were so-bad that the jaws were corroded, it was more the bodies were pitted. Things like screwdrivers and punches fared well, though the small number of taps and dies didn't fare as well, some of those were discarded. I used PB Blaster to thoroughly-coat the tools I kept, and a week later, I treated them to a second PB Blaster spray.
Bottom-line, the 'cleaning vinegar' did a good job of rust removal. I was able to salvage probably 85% of the tools, and yes, there was some decent stuff in there. Proto, S-K, Snap On, Craftsman, Herbrand, Armstrong, a real mix, worth it to go through it. And, worth the time to clean it. I ended up with a complete set of 1/2" drive impacts, and near-complete sets of 3/8" sockets in regular and deep sizes. It kept me occupied for a few hours, and I know where to go, to a local pawn shop, where they don't think every hand tool is worth more than new, to fill-in the missing sockets for cheap. Then it could be yard sale time, we're getting ready to move into another house.
those are all worth saving. Thought I saw a little Snap On in there. As Dave said, some light cleaning is probably all they need.