Toilet flush tank cleaning

caravantraveller
caravantraveller Forum Participant Posts: 1
edited February 2015 in Caravans #1

I have a 10 year old Bailey Pageant. Over time the toilet flush tank has become contaminated by dark gunge. Have tried various cleaners but with no complete or lasting success. The major problem is that the gunge makes the toilet holding tank smell, which
does not occur if if I do not use the flushing tank but pour  flush in by hand. Any suggestions?