Well yes and no. You can't really replace parts inside - say as a kit from Toyota, but you can take it apart and clean it up and put it back together again. Problem is, usually, getting the bugger off without a lump hammer. It can be a tricksy little blighter. I ended up having to drop my fuel take to get the stumps of the bolts out.
Replacement part isn't a cheap thing even a Milner one. I found that whilst mine looked like a dog, inside was clean as a whistle.