how to clean used glass carboys?

I picked up several used 5-gal glass carboys. They were stored in the basement of the former owner for several years. They held water during that time as part of an earthquake readiness kit. There seems to be some sort of residue left on the inside and I wanted to know what you all recommend as the best way to clean these out. I've heard of members using Oxyclean and bleach, but I am not familiar with reasons for either of these or others. Let me know what you do to clean your carboys and any suggestions you may have for me. Thanks- you're helping me expand my bedroom brewery to a twenty gallon potential.

Oxy-Clean Free works well. The "Free" has no added scent. Also with a glass carboy you can get a carboy brush to scrub the inside as you won't have to worry about scratching it.

It's possible that soaking it in Oxy-Clean and hot water for a day or so might remove the residue w/o scrubing.

the residue you mention could be calcium scale. if oxyclean doesn't get it out, a scale remover will. oxyclean itself may leave a white residue if you soak something long enough in it. a weak vinegar solution will clear it.

A soak in hot water and UBC (Ultimate Brewery Cleaner) will take care of it. It works really well. You can get it at Austin Home Brew.

Just be very careful when working with glass carboys and hot water. Too much temperature change and you can break one and then it gets dangerous.

CLR does a good job at removing Calcium, Lime and Rust deposits.

Bleach works well if you give it time (like overnight). PBW also works great and is faster.

GT

abracadabra said:

CLR does a good job at removing Calcium, Lime and Rust deposits.

Click to expand...

agreed. if it appears to be hard water deposits, CLR will take it clean off, as would Lime-away.
but both are very toxic and caustic, so rinse the living hell out of the carboys when done. then rinse some more