It may work for you and has worked for me good auld vaseline/petrolium jelly and grease all moving parts relating to and including the buttons its a clean harmless grease.
Also a short quick squirt of WD40 for parts that you cannot get at with the vaselene.
Another tip using vaseline/petrolium jelly
I use vaseline on my car battery terminals to stop/reduce the corrosive build up seen on many positive teminals also. To clean a corroded terminal without disconnecting bicard in water mix usually does the trick. Then clean it and vaseline it
Bob
December 2012