Is there anything to renovate the plastic holder? This set has such pronounced frosting, it is a shame to view them through such damaged and scraped window. Here a couple of the coins with frosting, and the awful plastic
I've read about using headlight cleaner and a polishing cloth. I've also read about using toothpaste. Something about the grit in it that basically polishes the plastic down. I've never tried either of these methods so your results may vary Those are some nice frosty looking coins!
I am in favor of leaving it alone, until the time you decide to encapsulate in a different manner. You could also replace the holder quite easily and for very minor expense.
As posted by members above, there are options, but each time I pick it up, I just want to break it apart so I can look at them properly
You could always use a Capital Plastics holder. Good looking, fairly cheap and usually available used at the LCS and eBay.