I wash all my tools and tool box with WD40. The only rust on my toolbox is where I've dented it or put deep scratches in it, but even then, it's only minor.
Never tried PB...
Thinking about this, I have a funny story about loooooonnnnngggg term tool storage. Out in NM at the family ranch, we went to an estate auction. While there, I bought a gooseneck flatbed. There was a toolbox on the front and when i got it home, I opened it to clean it out and ready the trailer for paint. I found 4 five gallon buckets inside. I was thinking, WTF? I tried to pick them up and thought, WTF is in there.
I got them out and was pouring the first bucket into a 55 gallon oil drum, when...SPLOOSH...I got fucking oil all over me. Well, you've probably figured it out by now, so yes, they were full of handtools! After a quick run through the parts washer, they came out spotless.
Apparently, the old man put them in there on purpose to preserve them. I talked to his grandson later and he also found some other tools the same way. We still aren't sure when he put them in there or why, but it worked!
Anyways, I'd suggest heavy doses of WD40 or possibly dipping them into oil and then placing them in bucket for easy storage somewhere.