Need some tips on removing rust of this M38:

I’m planning on using oxalic acid, which I already have… Any tips?

I know some say clean, other say don’t… My gut says clean, especially because there’s a name inside and I want to see if there are any decals underneath the corrosion…

Seller sold this to me as a ‘mustard camo relic’, however it could be that this camo pattern is just rust.. I do believe there’s a light camouflage pattern in purple and black applied though, the rust is quite severe.

Here’s the helmet:

(Liner itself is included as well, treating that one with leather care product/polish)

Name:

Please help, share your experience and opinions with me… Would like to become the best result possible.

Thanks,
Ken