NOOOOOOOO!!!!!!I have a 4 year old boy, too, and I know how they play on cymbals. He might actually abuse the cymbal and cause it to crack prematurely. To me, what I think the most impacting factor in burying a cymbal for any length of time would be the pressure from the dirt around it and the possible shifting of the dirt. The dirt itself, touching the cymbal, isn't going to speed up oxidation, as there isn't much oxygen and probably not too much nitrogen in the soil (unless you use certain soil). If you want to speed up the mellowing of a cymbal by playing it, position the cymbal on a sturdy stand, put on some gun range earmuffs, get some mallets, tell the family to leave the house for about 15 minutes, and roll loudly on the cymbal. Get the metal really moving! I've heard that doing this for 10 minutes or so can create a HUGE noticeable difference in the sound of a cymbal, usually cutting down on the high frequencies. I haven't tried it myself, because I buy cymbals that I like the sound of now. If I like a cymbal but think it would sound nicer if it were a bit mellower, I simply won't buy it and I'll wait until I find a similar cymbal that sounds mellower. It's that simple for me.
THIS IS WHAT I HAVE BEEN SAYING! Thank you! Someone else with common sense and reason.......finally! Bowing