Interestingly, several years ago in England, we purchased a 1/4 of the neighboring field to our house. When we put up the post and rail fencing, we dug up half a dozen or so Victorian bottles. They cleaned up beautifully and look "Like New" ... in the sense that the glass is in perfect condition.
What makes them look old is the slightly "imperfect" shape or bubbles in the glass or the words on the bottles... unless glass is damaged, it cleans up pretty well.
I think checking out flea markets or antique stores for old glass is a great idea.