At the risk of starting another thread on this... "excessive" leaning is a danger only at high power settings e.g. 75% or higher, specifically ones which result in high CHTs (perhaps 500F or so).
Excessive leaning alone just gives you a rough engine and a loss of power. No damage is caused.
During taxi, maximum possible leaning is the best thing - keeps the plugs clean.
Indeed, and is also much worse with a larger engine producing more power. The O-235 seen in most PA38s or C152s can barely produce 75% power, so can pretty well be run lean at most levels or power settings with no ill effect, but once you're onto a higher performance machine you really need to know how to work the red level properly.