Shot a cool special effect this weekend, but got some gunk on my lens. Did some initial cleanings, but it's still not clean enough, not as clean as it should be. What products do you use? What methods do you use?

Thanks.

WAIT! Don't go any furher . .wait till you get some feedback here!

Now's NOT the time to ask if you had a Skylight filter on your camera .. is it? SL Filts set me back 9 Quid . .. bit less than the . .er . .unthinkable. Get a SL - yeah!?!

Grazie

Do yourself a favor and take it and have it professionally cleaned and ask them to show you how to do it. When I say professionally, I mean PROFESSIONALLY, not some kid at the one hour photo who knows only slightly more about cameras than my cat! Then buy a protective filter and a cleaning kit you build yourself.
There are special lens fluids, special techniques, special tools and practice.

... but here's a quick and dirty, read all of it before you begin!

Always work from the outside in (so your not cramming junk into the corner)
Gently blow off the surface of the lens.
Gently dust off the surface of the lens.
Again, Gently blow off the surface of the lens and edges, or corners.
Use your special lens cleaning fluid and a lens cloth or lens paper (apply the fluid to the cloth NOT to the lens) and work in a gentle circular motion from the outside to the inside.
Continue until it is clean, changing papers or turning the cloth as needed.

Do I have to mention that before you even begin, that you WASH YOUR HANDS! With soap! I have seen and heard of all kinds of horrific scenes of people "cleaning" their lens, right after a big fried chicken dinner or hamburger and french fry lunch. If it's on your hands when you touch your lens cloth, it's going on the lens!

notes:
1. I prefer lens paper to cloth. It is lint free, doesn't streak, and I don't have to worry about if it's clean or not. I throw it away and get a new one.
2. Compressed air. Be careful with it. Don't shake it up, don't turn it over while spraying and don't get to close. The fluid that can come out of it can RUIN a lens as well as the pressure can blow small particles INSIDE the lens, then you're really screwed. Keep it back and use it for a good general dusting.
3. Buy a small pump blower to use up close.
4. Buy a good dust brush or two.
5. Alcohol is a common ingredient in many lens cleaners but it can RUIN special coatings so ASK a PRO before you buy fluid.
6. Take your time and go slowly and gently, the lens isn't going anywhere.

-hope it helps.