Hi Kathy. Bermuda grass is one of the toughest godawful things to get rid of. I did manage to clear a town lot in Tucson of the vile stuff and it only took me 20 years (actually, I probably got 90% of it gone in one or two and then it was just being vigilant around the edges). Can you believe that back in the '60s people there used to
water the stuff to make it grow on purpose?
I'll share one tip that will supercharge your powers: Use clear plastic instead of black. Clear lets the sunlight pass through and heats up the soil even more, and this makes the kill quicker and more effective. Ideally, you put the plastic down right after a good rain in summertime, and turn the lawn into a giant pressure cooker.
Either way, what's left at the end is a lot of dead thatch. As long as it's not full of seed heads, it's basically mulch and good organic material to help give your new clover crop a head start. Good luck!