Hello,
I use 100g oxalic acid for 1 liter of (very) hot water. I will soon try with less acid.
I first try with 20 minutes submersion. It could remove some paint, especially if you brush with something ... euh... strong (i dont find other word, sorry for my mistake).
I try stell wool, it's effective for rust, but agressive for paint. For more accurate work, I work with a nail brush (used when you brush your hand). If the fisrt bath is not effective enough, you make another one.
Next, you have to rinse with clear water and protect wiht linseed oil after dry.
I hope that you understand my bad english!
Cheers from France
Jean Loup