Find and trap several rust monsters. Let them loose on the golems. You have to love exceptional abilities and vulnerabilities. 
Honestly, I think a straight out fight would be workable. They don't have DR, you don't have magic weapons. As long as the PCs can retreat, heal, and try again they should win.

Honestly, I think a straight out fight would be workable. They don't have DR, you don't have magic weapons. As long as the PCs can retreat, heal, and try again they should win.