Add this to your ~/.bashrc
# Quick way to rebuild the Launch Services database and get rid
of duplicates in the Open With submenu.
alias fixopenwith=/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister -kill -r -domain local -domain system -domain user
Then run:
$ fixopenwith
From your terminal.
Thanks Getting rid of Open With duplicates – All this for the tip!