If it were me, I wouldn't want to restrict my macro names to Dropbox limitations. (Easy for me to say, I've stopped using Dropbox. 
)
In all seriousness, @ronald, what's your motivation for cleansing your macro names?
If you want to use the Keyboard Maestro sync feature, my recommendation would be to avoid direct use of cloud storage. With that said, I think there are others on the forum that house their sync file in Dropbox. Maybe they will weigh in with some suggestions. (I shared my sync approach here: One Approach to Synchronize All Macros Between Multiple Macs)