Depends.
Assuming you play vanilla or PTW, the main question is if that city holds an unique rank. If it does and if there's actually a bunch of other cities sharing a higher rank, disband it. You'd then gain an advantage through the rank-bug in vanilla/PTW.
If that useless city already shares a rank with at least one other -not so useless- city, you'd gain nothing by disbanding with regards to rank-relevant corruption. Your better off keeping it.
In C3C, you would be possibly better off disbanding it if the number of working tiles is small (-> low spt/commerce) in comparison to higher ranked cities. But already existing corruption/waste-affected/influencing city imps like market, factory, courthouses etc should be considered as well!
Also note that abandoning a city will increase unhappiness in the nearest city, which may let that city slip out of WLTKD - with the effect, that shield waste might stay on the same level (or worse) than before (also depends on which city gets the 'cruel suppression' unappiness).
In any case, I recommend to read alexman's, Qitai's & DaviddesJ's corruption threads in the Strategy Articles Section.
