<HTML><HEAD></HEAD> <BODY dir=ltr> <DIV dir=ltr> <DIV style="FONT-FAMILY: 'Calibri'; COLOR: #000000; FONT-SIZE: 12pt">I had a set of Bosendorfer casters that were frozen as well.  I boiled them in vinegar to soften the unwanted goo.  While still hot I dipped them in water and started wiping off the rest of the crud.  I then followed up with a good couple of hours of buffing.  Replacing casters definitely takes less time than trying to save them.</DIV></DIV></BODY></HTML>