Red Devil lye
Red Devil lye, a retail-packaged form of sodium hydroxide necessary for soapmaking and some types of candlemaking, was discontinued by the manufacturer (Reckitt-Benckiser) for reasons that remain unclear. The primary suspicion is that the US government was putting pressure on them to discontinue it because of its use in illegal "meth labs" (methamphetamine manufacturing); this would seem part of a broader campaign to prevent US citizens from having access to an increasing number of basic chemicals.
Some online retailers continue to provide sodium hydroxide, but often with restrictive requirements.
As of 2005-08-11, The Hypertwins could (only) find this locally at Kroger on Hillsborough Road -- not South Square Target, K-Mart, Harris Teeter, or the Lakewood Food Lion. It must have been discontinued soon after that (or perhaps it had already been discontinued and that's why nobody else had any).