How to Delete Old Offline Associations

I have had to replace my desktop - I had offline association at that time - I
replaced desktop gave it the same name but changed file locations to a usb
drive - now I have to sets of offline associations - how do I delete the one
that does not exsist any more? It has also increased the amount space
allocated for offline files. If I can delete the old association I should
correct the space allocation as well. So how do I delete old (no lnger any
good) offline associations.