Well it doesn't take very long, I'd say at the most an hour in total so half hour a side?
There are kits and formulas for it you can buy, I think; I have all grits of papers on hand already because I use them in sharpening planes and chisels for woodworking, and I also use them when I finish alkyd paint onto wood. If you bought them all it would be some dollars.
I just take a little piece maybe a couple inches square, wet it, do both sides, go on to the next. I wipe off the debris after each. I guess the slowest part is going close to the little nibs but no need to go nuts about it. I always go -vertical- up and down with the sanding versus circular, it works better, for this.
Because you are progressing through grits gradually you just need to spend a short time with each. You'll see the debris in the water.
When I get to the last glaze I am going circular but the rest I stay vertical.
There are formulations like PlasticX I think it is but I believe they are actually some kind of solvents anyway I can't vouch for them I didn't use them.
The main thing is if you work with the 600 first pretty well, you will have removed the outer surface haze/discoloration, from then on it's just removing scratches left by the 600 by going successively finer.
Normally all these fine papers are wet-sand papers. The key to the water is it's a lubricant of sorts and importantly it floats sanding debris (and any grit that might detach from the papers, but, normally that doesn't happen) away from the work. I just have a bowl of water, dip the paper in it, and sand gently up and down covering all the surface, wipe with a paper towel, do the other side, and go to the next paper, it's not hard.
I suspect it's not too different than any sanding task where you generally use the coarsest paper you can to start out and then work finer, but the finer grades are to sand out the scratches left by the previous-coarser paper as opposed to really removing much material. When you are done it should feel really smooth to your fingers and it should look better. I confess at the end I rubbed in some Armorall, since they are plastic, but I doubt that actually does much of anything. Good luck and I hope that helps a little, and of course there's always the option to just spring for new lights but I think you can get a big improvement with the sanding.