If you have really old glass, you could artificially age it chemically, as the first attempts at anti-reflection coating were done, after it was observed that glass which had formed a tarnish had better transmission and contrast.
That could be fun, with no big investment.
I have a 6" Dagor from ca. 1906-8, it has an absolutely beautiful and uniform deep blue bloom on the front and rear external surfaces. Sadly it has no bloom inside, where it would do the most good.