He have a 99 528IT and I was wondering if anyone has a remedy on clearing out the condensation that forms on the inside of the headlight cover?

Take a trip to your local target or similar store. Ask a manager if you can have those little packets that absorb moisture from shoe boxes (looks like a little splenda/sugar sized packet and say "do not eat" all over them). Place them in the panel where you install your headlight bulbs and give it a few days. Should absorb all your moisture

I own a 07 M6 & 05 M3. When my driver side M3 light got cloudy I had both lights polished by Germain BMW of naples. WASTE OF MONEY! They claimed they could not be made clearer because the cloudyness was on the inside:nono. One of the techs pulled me aside and told me about Dr. Headlight, Before dropping some serious cash I gave them a call.
!!!BRAND NEW!!! I tell ya!
Look them before tossing out your new light.
No guarantees but it worked for me! :redspot
See ya at 190+

Are you sure it is on the inside? That is the biggest misconception about yellowed headlights. I know E39s are pretty bad about getting foggy/yellowed lenses after a few years. All they need is a good polish - or at worst a wet sand and then a good polish to get the oxidized/etched layer off.