Remove all leading and trailing whitespace; change all instances of more than one whitespace character to a space; lowercase; remove punctuation. Then create a 3-character frequency count and match it against the 3-character frequency count for existing fields. If the percentage match is over a certain level, add possible matches to an array. Sort by percentage match.

Now either choose a record (or field) to merge with, or mark the record as unique and move on. Hopefully you won't have to manually deal with too many records.