You can call the "Hold-Heet" folks for a new liner.  There are two
liners available: one has rounded corners at the top rim and the other
has the squared corners on the top rim.  One is older than the other.

I purchased one of each for my two pots.  Of course, shortly
thereafter I discovered the use of plastic squeeze bottles and I would
never go back to the aluminum liners.  My liners sit there on my top
shelf waiting for me to need a whole lot of glue at one time.  I think
I would still use the plastic bottles.

D.L. Bullock    St. Louis
http://www.thepianoworld.com/