Database Design: Linking 'vague' entries to associations?
One possibility would be to build a list of the values you currently have, and make users pick from that list, or enter it separately to get it on the list.

I do this all the time in various web interfaces - when I need to pay a bill through my online bank, for example, I first have to go create a payee. I curse this when I am only paying a one-time bill, but I love that I don't have to enter my account number and other details every time I make a car payment, mortgage payment or pay an electric bill - only the first time.

This will also reduce the noise from "almost" duplicates, for example if one person spells it Weber's and another spells it Webbers hopefully the second user will just use the first even if they don't think it's correct (and if they're both wrong you still only have to correct one row).

If you make users see the long-term benefit there should be no screaming about the up-front pain.