All alcohols act as a co-solvent that allows water to mix with gasoline rather than separating out and dropping the to bottom of the tank.

The trouble with most store-bought alcohols is that they already have water in them. Read the label. If it's 80 percent isopropyl alcohol, it already has 20 percent water, so you're better off using a product that has little or no water in it. Heet is mostly alcohol, and it should be "dry" (read the label).

Oxygenated fuel already has 5-10 percent by volume ethanol, so any water will have a greater propensity to dissolve into the solution rather than separating out. In CA we have oxygenated fuel year-round. In many parts of the country oxygenated fuel is only supplied during the winter months.

Duke