i have same problem in cultus2004. one light was looking very dark than the other one. i opened them and washed with surf and plain water. dried them in sunlight. and again fix them back lot of improvement. i didn't opened the seal of the headlight just removed the bulb and wash the light from their no need to insert any thing in it other wise u can damage the reflector. just u can put some soft cotton cloth in to dry the water from it.
as i mentioned lot of improvement in light but still i m not satisfy with the performance. problem is when u face strong light of vehicle coming infront u can't see any thing. i don't know other people have same like problems. more over i feel light angle is above the road instead of on road so i tried to fix it by moving a bolt in headlight to fix it. i tight the screw full even then light is up and scattered. i wants help how to fix it coz their is no more room to tight the screw.
i thought to replace whole lights with cultus latest model white crystal lights and some one told me genuine lights r costing Rupees 12000/- he offered me second hand in 5500/- he said these r genuine one. who knows he is denter.
so any one can help me what to do how to improve it without extra expenses. coz i m planing to go to Gujranwala on Coming Eid. so i want headlight perfect. on highway u know busses and trucks have extra strong lights.