Smelly Glaze & Mould Or Mildew
Some customers are reporting a sulfur-smelling stench when opening glaze buckets. Whilst this is unpleasant, it does not mean your glaze is ruined. The odour is caused by organic ingredients (e.g. gumming or suspension agents) breaking down and causing bacteria.
A capful of sterilising fluid (some people even use bleach) per 5 gallon bucket should eliminate the smell and won't affect the performance of the glaze. As a guideline try adding half an egg-cupful at a time. Make sure the glaze is mixed well after adding the fluid and wait a few hours. If the odour remains, try adding a bit more sterilising fluid or bleach.
Moulds play an important part in nature by breaking down dead organic matter and they reproduce by means of tiny spores that are invisible to the naked eye and float through air (both indoors and outdoors). Mould and mildew occur due to the product and storage conditions e.g mould cannot grow without water or moisture.
We recommend removing mould using a household, plastic sieve. Again, a capful of sterilising fluid/bleach may help. Also, it is good practice to ensure the lid is kept on the glaze bucket when not in use.
The following article produced by the USA Environmental Protection Agency "A Brief Guide to Mold, Moisture" is interesting.