Tripecac
What is the easiest way to delete a marker in the track view?
Consider reading the documentation when you want to know how to do something, you'll get the answer MUCH faster than waiting for someone to reply to a forum post. It took me less than 10 seconds to type "Markers" in the Index, see "deleting" indented under it, and find what BobF found.
If you need to delete lots of markers at once, though, I'd recommend a different technique.