I am posting this as a public service to myself on how to delete duplicate rows from a mysql table.
In my case I have a unique column id on each row. And I have an indexed column, call it match, that I use to determine duplication.
In short so I can find it next time what I do is
delete t2 from table1 as t1, table2 as t2 where t1.match = t2.match and t2.id > t1.id;
This works and takes about 2-4 minutes on a table with about 280K rows and 35K duplicates.
I've only tested this with isam tables, I know this can be done other ways and can be gleaned from the mysql documentation, but this way, when I can remember it, seems simplest.