I hadn't used my espresso machine in quite some time (DeLonghi EC-701) and I thought that before I make some espresso, I'd best give it a thorough cleaning and a descaling.
My question is about descaling solutions/liquids.
I don't wish to pay $14 a bottle for my next pre-bought solution.
I've also read about the problems with using vinegar in espresso machines.
Does anyone have any experience with a homemade citric acid solution? What was your "recipe"?