no there is no way to take the front lens off. it is part of the housing, which is removable, but you will not be able to clean it because the hole is only big enough for the bulb. flip side is, thats exactly why its probably not that dirty in there, assuming your bulb sealed well against the back, and that theres no holes or anything drilled in them (some guys do that to stop condesation).
When i changed my headlights to the ultra clear housings, my headlight output was noticably better. combined with new bulbs and a 3g alt, theyre pretty damn good.
for cheapo cheaop i'd say sand the yellow off, and buy new bulbs from AZ