A and C has a point here: try to reduce power before completely closing throttle - to cool the engine a bit...
When regarding to CHT it's important to know that low CHT itself isn't so bad (otherwise, how would you start the engine if CHT shows zero without causing any "damage?"), it's the change of CHT that will and does hurt the engine.
Also, spark fouling during PFLs shouldn't be a problem, since spark fouling is usually caused by prolong idling on the ground (1000 RPM or even less), but during PFLs the RPM is around 1500, and they usually don't take more than a few minutes (compared by waiting for more than half an hour for IFR departure from a busy airport at 1000 rpm).