Cleaning Glass vessles?

I have noticed my Erlingmeyer flasks are starting to get kind of hazy. Is there something i can use on the to get them to sparkel again?

long soak in warm PBW followed by a Starsan soak should do it.

If your local water is hard, the haze may be calcium carbonate buildup.  In that case, adding an acid to the vessel may clear up the deposits.  I suggest distilled vinegar or 88% lactic acid as options.  StarSan is also a good acid.  You should be able to add a small amount and swirl instead of having to fill the vessel.

If that doesn’t do it, then the glass may be getting etched by something like a strong cleanser.

Not hijack the thread, but I have an old “medicine” jug I was going to repurpose for starters and such. I have no idea what was stored in it, but it appears clean. I was planning on using pbw, but is there anything else I should do before using it?

Without knowing what was in it, I wouldn’t use it.  Or at least I’d want to be reasonably sure it never contained radioactive material and I’d probably autoclave it.

[u]Nuclear Wessels?[/u]