Originally Posted by
DorkDisk
Confirming the "kinda fit"
Heres a pic of what I beleive are the hoods and levers in question
This is the first iteration of 6400 levers with the later 6400 SLR hoods on them. The first iteration was based on the 600ax design rather than the 600ex design. The OP has the latest version of the 600ex design (6209). I have both the first iteration of the 6400 levers and 6209 levers and can confirm that the hoods from later levers don't fit properly.
To clean hoods, I use Goof Off. It's dead easy, loosening the grease and crud.