Question Author
Follower the advice regarding rice and Ziploc bag, put bag in airing cupboard for 36 hours, USB drive worked perfectly!
Thanks for all your help!
The files were backed up as Old_Geezer suggested, but |I wouldn't have known what files and folders were on there, which leads me to another question!
I don't know how to link questions but if you want to see it I'm sure you'll be able to get to it via my profile.
Thanks again