No - any treatments such as SBK for tree stumps are designed to stop them growing again - rotting down is a natural process and takes time.

I think it depends aswel on how big it is.

I had 2 that were maybe 3 foot tall, both died down in winter and rotted.
I left in the root and now one has babies each growing well.

i dug the root out and it was very healthy so it may be worth leaving for awhile to see what happens.

Thank you for the info on Cordyline, may just leave it in and see what happens.