Athlon Thunderbirds, Duron Spitfires and Morgans were easy to unlock with a sharp 4B pencil line on each of their L1 bridges. That's the method I used on my 1GHz Duron Morgan with great success ( 166MHz x 6 @ 1.3V )
All Athlon XPs are unlockable using conductive paint, due to the various cores in circulation today, you'll need to search the web for detailed instruction because the location and function of their bridges is different.
It is also possible to unlock AXPs with a metal wire loop between some pins, once again, do some research before atempting anything.
Fok Speling Misstake