Does the minus sign or underscore in css do anything?

This question is similar to the one I asked here. I am cleaning up some files and I came across this in this css:


.something
{
  height: 33px;
  -height: 34px; /* does this do anything?? /
}

and


.something
{
  _width: 150px; / does this do anything?? */
}

EDIT: Okay, so the _ (underscore) is a css hack for IE, which is fine, I'll just leave it, but what about the minus sign, does it do anything at all?

Also, we are not supporting anything below IE 7 anymore, so if anything is a hack for IE6 I can take it out.