I have a collection of range objects, called collXcells, and each has a
key cooresponding to the range's R1C1 position (each range is only 1
Excel cell). I.e. if there is a range object that is the A3 cell, its
key for collXcells is "R3C1".

Is there any easy way to check if a key in the collection exists? and
if so remove the item associated with that key? (a way easier--and
preferably more efficient-- than looping through all the collection
objects keys, that is).

Thanks,

-Abe