If you absolutely must snipe individual files while leaving the rest of the cache tree alone, try replacing the locale name with "*", I honestly don't know if CMD.EXE's "IF EXIST" conditional works on wildcards at all. Maybe prepend an 'echo' in front of the action command so you can see what it would have done before trying it for realsies.
If you still need it done and CMD.EXE can't do it, then I'd advise either learning PowerShell (and God have mercy on your brain), or installing a copy of Cygwin and just scripting in whatever language you prefer using (Bourne variant, Perl, Ruby, Lua, etc).
Good call on looking for running processes first. Most people wouldn't think of that.