Luca58, two things. First - I've had this happen in one or two remotes I've owned. If you haven't tried it yet you might want to take apart the remote and carefully scrub away the residue. Use caution when doing this, but sometimes the remote can be brought back to working order by cleaning away that gunk.
If that doesn't work or if you don't want to do that, I have the codes in my Marantz RC9500 remote. I don't know if the captured codes can be used or translated for other universal remotes... not sure how that works.