Better Bottle Cleaning?

Anyone have good tips for cleaning a Better Bottle?  I used one for the first time last batch.  Manuf says dont use a brush on the thing.  I dont want scratches that hide bugs so I comply.  However, I am having a heck of a time getting this thing clean.  I mixed up the proper amount of PBW and 100F H2O.  I then let it sit and soak overnight, shaked it again like a cat that pissed on the carpet and still nothing.  Any ideas?  I am thinking of using my brush, putting the thing in the kids room to collect loose change.  I like the light weight, but if I cant clean the thing what good is it.  Any suggestions on how to get it clean?  Glass, I shoulda never doubted you....

Ryan Church