Wash them clothes....how?

[Ukprepper88]

I'm thinking of using something I saw on a tv programme a year or two ago (Victorian farm I'm sure there be a youtube video about this but as I'm on mobile Internet I can't search for it for you)... Basically the Victorians apparently got a barrel with a spout at the bottom filled it up with ash from their fire (about half or 2/3 I think) then poured boiling water slowly into the barrel so it seeps through the ash and trickles out of the spout a slightly greeny colour which they said was a lye solution (lye is used in soap making) which is what they used as washing liquid... But I definately want to try it before I need it just to make sure it really works as I don't take anything for granted!