mineral build up on rims of plant rooting glass....help

I am calling it a mineral build up of some sort but don't know what it is in reality. If any of you have any experience with successfully removing the build up that often happens when keeping plant rootings in the same glass container for a while, I would love to hear about it. I have several nice vases that have this build up on them and it bothers me that they look for cruddy in that area.

Any ideas? Thanks for any and all feed back.

Ruby