Carbon Build-up causing leaky valve seats on local evos?

[Kracka]

The only way I've used MCCC is to spray it in the spark plug hole to let it soak on the piston (could do the same with SeaFoam, always change the oil right after this method) or to spray the MCCC into a vacuum line while the engine is running (you'll need to hold the idle around 3k RPM to keep it from dying).