Technical Its the "Pits"

Starting to work down the fenders on the Auburn. This one is fairly solid, but has these pits in it. It is too cold here to setup my electrolysis tank, and actually this was cleaned to this point that way, i'm not certain that more treatment will help.
Question- what can/should I do to get this cleaned enough to coat and seal with epoxy primer so that I can proceed with filling, and eventually paint?

 

Why not use something like Evaporust? Just soak a cloth with it and lay the cloth on the fender- little while later, the rust is gone and you can clean and prime.

 

White vinegar soaked bath towel. Let it sit for 36 hours, remove, and rub it with Metal Prep. Primer at leisure, the prep will protect.

 

i would have it blasted.

 

Thanks everybody!
I was not sure 'evaporust' (or vinegar) would do it. I might have it blasted. thanks again!

 

Molasses, vinegar, evaporust, blasting. Whatever it takes to get it clean.