Go to your local automotive or electronics shop and get a can of electronic contact cleaner. Use the included spraytube to spray inside the sockets, it should melt the paste away rather quickly.do not use this stuff indoors
EDIT: It looks something like thishttp://www.cpcares.com/TAE/puretronics/TAE-5000.html
Some are greasy, avoid these. If you can get a can that's based on HCFCs then get that as it will work better than the non-HCFC compounds which are coming to market due to the CFC/HCFC phase out.