I think I am the only one who has never had a build up problem!
And for the first 6 months olf DDs life, I didn't know you were meant to use half the amount of washing powder AND used nappy san, so I was using the max amount of washing powder (as in the amount for heavy soiling in hard water) AND a dose of nappy san in every wash! . Never had problems though and that was with no extra rinsing before or after. Just one 60 wash. Lol. Now we use one bold 2 in 1 tablet and thats it. Always rinse before the wash though but don't bother at the end, unless I have a specific reason to (ie DD has a sore bum).
You are all going to think I am mad, but we ran out of loo roll the other day and I couldn't go out to buy any as DD was in bed and DH was working till 11pm. So I used washable wipes (dry) all evening (weeing every half hour!!) and I actually prefered it! I have been using them ever since! . We still have the loo roll there but for wee i have just used one and shoved in nappy bucket (which is in the bathroom anyway). Hardly any wee actually goes on the wipe and it dries you much better than loo roll does! Wouldn't have done it if we hadn't run out of loo roll but I might actually carry on! We are still on the first loo roll since DH bought it that night, where as we were going through at least one a day before (I can't stop weeing as baby is on my bladder!). So will defiantly save us money. Not something I would admit to anybody else though!