I blasted mine and made one mistake.
I did not get ALL of the burlap out.
That stuff will hold sand like you wouldn't believe. Wound up pulling the covers off and doing it again. I would think you can leaave the springs in. Take all cloth, burlap and foam out. Also, if you just have a very fine layer of rust, I wouldn't blast it at all.
I used some Permatex spray navel jelly.
Stuff turns rust black and seals the metal.
Worked great under my dash and inside my kick panels.

Dave

 

Ben,

I stripped my buckets down to the metal frames. Seperated the bottom from the top. I lightly sandblasted the frame assembleys and then coated with POR15. Give the springs and such a close inspection. I had a few broken springs which I then repaired. I also had the buckets recovered with new foam and seat covers. I had the shop add a little extra thick foam around the outside edges of the bottom seat springs for extra reinforcment. This will help the springs and keep them from sagging over the years. This was the shops recommendation and it worked out great.
I sit up nice and tall in my new buckets now.

------------------
FastSS396Man
Brian

Fastss396, Fastss396,Fastss396,
Fastss396,Fastss396,Fastss396,Fastss396,Fastss396,Fastss396,Fastss396
69' SS396 Chevelle
L78 396/375hp
M-21 Close Ratio
Cortez Silver
10 year Resto
It's brand new again!
02' Harley FatBoy, Diamond Ice Pearl and lots of chrome!
ACES# 3466