I’m new to the group and had the same question. I restore vintage garden tractors & often use vinegar to remove surface rust & thought this might be a good option for the erector sets. I keep a small plastic tub with a lid out in the garage and was going to try it. It is best to let it soak overnight and rinse well under running water, you have to physically wipe the rust off with a rag, if you let it dry, you have to start over. Now to keep it from rusting again, I was thinking about a spray wax.