[wizofaus]

Why's there a need to? If it's highly unpleasant and there's a shortage of people willing to do it then surely it's a perfect opportunity for the development of self-cleaning tanks... As it is most of the truly unpleasant jobs of previous centuries don't exist anymore - if someone had found a way to make gong farming pleasant (look it up!) then flushing toilets and town sewerage systems might never have been invented...