This had the potential to cause a lot of issues the way it was. Moving the actual functionality for cleaning, filtering, and applying extras to their appropriate classes allows for less redirection when calling into the code. Modification as a class was essentially a shell around things that should have just been a single call.
This change ended up being three-fold:
1. Remove the entirely unused header field filters
2. Move filter running to their appropriate filter classes
3. Separate out DatItem filters into more managable private methods
