Hi Fellow troopers, TK267 here. I took my armor out of the box and I too hav ethe yellowing issue. I bought it from Holywood FX about 15 years ago. I want to display it, but need to get rid of the yellowing. I'll be trying the technique in the industructable, I did try with 3% HP, but only made it a little better.
I'll heep you posted.