This article is from the Sourdough Starters FAQ, by Brian Dixon briandixon at hotmail.com.
Always cover proofing bowls with plastic wrap and poke a couple of
holes in it so gases can escape. Always use non-corrosive bowls,
containers, and utensils (glass, wood, stainless steel). If the
temperature in the proofing area varies much at all, wrap the
proofing bowl in a towel to help maintain an even temperature and try
to find a better place to proof the starter.
 
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