It really sucks, but you have to get rid of everything. All those hours of playing fun maps were bothering me because my Heavy score was around 1,500 while my pyro score was like 25. I reset it and found out that everything went away, including times. So there goes any evidence of my 100+ hours on TF2 and it got rid of the achievement counter thing so that one for doing 1001 kills as Scout or whatever was reset so I have to start doing that all over again.
But you keep the achievements you've already unlocked, though...