it brings the discolouring right out, but i only use it when stuff is actually dirty. most of the time it's not used for long enough to need more than a rinse and a cloth.
i used a bright pink tubbed one, seen it on tv...i left a fermenter with it sitting in it, i just filled with cold water and tipped a scoop in and stirred...it left a crust lining on the inside of the fermenter..this stuff MUST be dissolved into hot water otherwise it seems to crystalise.