Just noticed a couple of errors early on in this thread where sodium hydroxide is mentioned for raising pH of WMO.
One poster said Drano was lye. It isn't Drano contains lye (which is sodium hydroxide in the States) but also contains salt, aluminum pellets and sodium nitrate.
Another poster says you can obtain "NaO" instead. The proper formula for sodium hydroxide is NaOH.
Lye is still available in bottles in Vermont at the hardware store, so it seems to more a matter of low demand these days than unavailability for any security reason..