I just had one headlight assembly replaced and the other one is dirty on the inside in comparison. Is there a way to clean the inside of the headlights?

Im in the same situation- a small accident required one to be replaced.

Ive seen cleaning kits out on ebay. Im assuming the yellowish stuff is on the outside. Ive taken some polish to the light but doesnt do much.

(scroll to the bottom, also see an example on a seville)

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7942597478&category=33710

There is a kit from Eastwood Company that uses an Autosol polish. I used it. Headlights came out like new.