Picked up this yellowed battle platform from a local sale and went gave it a bath in peroxide and let it sit for 12 hours or more? This time it left the decals on because they are in good shape so I took a chance and left them on. And they are just fine if not better!! I am so happy I just may keep it. Might. Take a look at the clear plastic part. I used this car stuff called plastix to clear it up. I'm kicking myself that I didn't take before pics.
More info on this process is that I am sure you need sun to do this. It was inside all day and once I got home I put it outside and that's when it really started to get white!!