I have not had my MX500 break, never thrown them down or treated them harshly, but they have "clanked" against a table or two in their time. I'm surprised that yours would break from something so minor. Most earbuds have such little mass that droping them usualy doesn't cause much damage, just like droping an ant or something, no structural or internal damage is had upon the subject because its mass is not enough to creat massive hemoraging of the housing or shell of said droped thing. I have clunked a bunch of earbuds against tables and door and walls and the like and none of them have ever changed their sound because of it.
You can try the sucking/blowing on the driver, I have done that myself, but be careful.
Hope your warranty is still active on those MX500s, although for such a cheap headphone its rather a bother to collect on the warranty.