chappo1970
Piss off or Buy Me A Beer
On a serious note - just unscrew the lid a little if you're keen to keep the airlock in. CO2 will escape via the screw thread rather than through the airlock, the positive pressure should keep any nasties who could otherwise wind their way through the screw thread out, and you'll be happy.
+1
Or do as I do and remove the rubber O ring altogether. Simple and effective.
Cheers
Chappo