Golfed this is way shorter than mine... though my technique could be used in other places, this one is a much lower par for this hole :)

Update heres a sneaky golf trick, tho...

delete@h{grep!/^t/,%h};
[download]

You don't need the keys... sure it will look at the values, but it will only try to delete the values as keys if they start with a t, and they should be deleted anyway, and if it doesn't have a key that matches it, it ignores it... save 4 strokes... woohoo

                - Ant