Leaning to MAX EGT will raise the Temperature in the cylinders and is likely to damage the valves and if continued for too long the cylinder heads.
A far better course of action would be to take the advice in the Lycoming service instruction on the subject. This publication advises the following action for the PREVENTION of spark plug fouling.
Shut the engine down in the following way , Idle the engine at 1200 RPM and check the Mag drop on both Mags, increase the RPM to 1800 RPM and hold it for 60 seconds, return the engine to 1200 RPM and immediately set the Mixture to ICO.
Using the shut down procedure in accordance with the Lycoming SI virtually eliminated spark plug problems with my Cessna 152 fleet when introduced by the operators who leased my aircraft.