get yourselves a can of this stuff,,$22, I was told about it a while ago. [bit slow on the uptake]
make sure it's the CO type, it won't harm the plastic plugs.
sprayed the CDI box plugs & the coil plugs yesterday, has taken the buzz out of the handle bars & is much more responsive with only that little bit of attention. Am planning on doing the rest of the plugs over xmas