320 grit dry sandpaper followed by 400, 600, 800, 1000, 1500 and finally 2000 grit all wet sandpaper wiping down the surface with a mixture of 25% acetone and 75% isopropyl alcohol to speed up the transition between grits.
Then 2 applications of Novus 2 will have it back to NOS near mirror shiny pink.
This is one of several topics I posted showing how it's done in about 10 minutes a side.
http://www.classicrotaryphones.com/forum/index.php?topic=20531.0You've damaged the surface chromophores using those oxidation chemical to the point where they are not absorbing any light frequencies thereby reflecting all light making it look white, just what bleach and peroxide are used for to brighten dingy white sheets.
All that damaged plastic surface layer must be removed to expose the original plastic pink chromophores, make it look like new. 320 dry will save time. 400 to 2000 is recovery from the rough 320.
Everything you need to know what you did and the only way to recover from that damage is in this topic.
http://www.classicrotaryphones.com/forum/index.php?topic=23386.0PS: bead blasting using any media will ruin the plastic, will never be smooth ever again without starting with 320 grit sandpaper on a sanding block to even out the pitted surface. So, start with 320 and leave the blaster in the closet.