With old iron we used to just put the condensed water from the dryer in the iron to stop limescale building up - very hard water area. That iron eventually broke, bought next iron which said not to use tumble dryer water and instead use self-cleaning thing, which turned out to be a right faff once a month. Iron now so gunked up it no longer works properly so have bought iron three. This one also says to not use tumble dryer water and instead the self-clean thing, only this one is once a fortnight! 
Am I going to do something awful to the iron if I just use the tumble dryer water instead of faffing around with the cleaning mechanism.