On Sat, 29 Mar 2014 18:49:45 -0700, Oren wrote:

Stick a set of pliers handles down from the top ..
The top and bottom top parts are threaded - separate them.

I tried all sorts of pliers to remove the basket from below:
http://farm8.staticflickr.com/7346/1...c8dfa1a1_z.jpg

I even tried circular vise grips:
http://farm8.staticflickr.com/7383/1...0d0e981d_c.jpg

In the end, I chiselled off the cast aluminum lock ring:
http://farm4.staticflickr.com/3714/1...2fab2157_c.jpg

And, then I banged the basket up with a rubber mallet:
http://farm4.staticflickr.com/3780/1...3646487d_c.jpg

The good news is that the basket is now out of my sister's sink:
http://farm8.staticflickr.com/7009/1...7ff88475_c.jpg