Does CLR Wear Out?

Does CLR wear out?
Is it possible what is on my glass is impervious? I have two small brandy sniffers with what I thought was severe calcium buildup that I finally brought up the 'big Guns' after failing to remove it with Amway Scrub Buds and Amway LOC Soft Cleanser, both superb products, and soaked them in CLR for a couple days.
Admittedly, my CLR is a couple, or more, years old so, could that be the reason for my failure?

Author: Shatto