One of the purposes of the inner cover and of the burlap bag and of the
hive mat seems to be the prevention of a buildup of burr comb from
sticking the outer cover down. The telescoping outer cover is difficult to
remove because you can't pry against anything to pop it off.
 
I use insulated inner covers in the winter and I leave them on in the
summer because they are easy to pry off even when stuck down with burr
comb. Naturally it would be better if the bees did not build the burr comb
in the first place. I find if you make the space between the top bars and
the inner cover about 5/16 of an inch this burr comb is minimised. the
difficulty is partly in the non-uniformiy of the frame height in the
supers. A rim height of about 3/16 of an inch works best for me.
 
Donald Aitken
11710-129 Street
Edmonton Alberta Canada
T5M 0Y7