Lye is a hydroxide, either sodium hydroxide or potassium hydroxide. The word lye most accurately refers to sodium hydroxide (NaOH), but historically has been conflated to include other alkali materials, most notably potassium hydroxide (KOH). In order to distinguish between the two, sodium hydroxide may be referred to as soda lye while potassium hydroxide may be referred to as potash lye. Traditionally, it was obtained by using rainwater to leach wood ashes (which are highly soluble in water and strongly alkaline) of their potassium hydroxide (KOH).
https://en.wikipedia.org/wiki/Lye
Lye is a hydroxide, either sodium hydroxide or potassium hydroxide. The word lye most accurately refers to sodium hydroxide (NaOH), but historically has been conflated to include other alkali materials, most notably potassium hydroxide (KOH). In order to distinguish between the two, sodium hydroxide may be referred to as soda lye while potassium hydroxide may be referred to as potash lye. Traditionally, it was obtained by using rainwater to leach wood ashes (which are highly soluble in water and strongly alkaline) of their potassium hydroxide (KOH).
