I have a 40 year old gas-fired boiler. It's pretty much a metal can
with no insulation around it. As a result a lot of heat escapes and
overheats the room it's in.

I realize that insulating it probably wouldn't make it more efficient
but what I'm interested in is keeping the room with the boiler a
little cooler.

Is there a way to insulate it? I asked at Home Depot-- the Building
Materials folks said to check in Plumbing, that a water heater blanket
might work. The Plumbing guys said no, a boiler gets too hot (the
water's 160 or so degrees but I don't know how hot the boiler itself
gets) and you can't use a water heater blanket on that.

Any ideas?