You see this whole q-tip business confused me - i had no idea what a q-tip was until i did a google image search for it last night and saw COTTON BUDS!!! you damned americans with your weird words for objects .. they're called COTTON BUDS!!
anyway i used a COTTON BUD (not a q-tip) today on the lens and i successfully played a quick match on pes2

so it seems like it worked fine (note: i beat norway 2-1 with wales. simon davies scored a spectacular scissor kick and john hartson broke away and finished well

)
Cleaning the lens seems to work really well and it's fairly easy. here's my quick guide
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Turn your ps2 over so you can access the bottom of it - there should be rubber covers over screws and some harder covers aswell. take the rubber covers off (you can just use your nails) .. but with the harder covers use a flat-head small screwdriver to get in any of the edges and they should just pop-up.... i think there are approximately 10 holes for screws in total.
Get yourself a + head screwdriver and take all 10 screws out - take note of where the longer screws go - i actually set my screws out on the table in the formation that they came out of the holes.. so the same screws were going in the same holes i took them out of. ..
Once all the screws are removed, turn the pes2 over again so you can see the normal topside and just slip the casing towards you carefully - bring it towards you a bit and then just fold it out to your right hand-side (if you're looking from the normal front-on view)
**make sure you don't rip the cord connecting the eject buttons to the pes2**
once the case is off you should see a thing saying caution : laser blah blah blah don't stare into it.. square thing with 4 VERY TINY screws on (you need a small + screwdriver to take these off - should be no problem tho)
once the casing for the laser disc is off you should see the tiny little laser eye thing which is just a little clear disc thing inside a sorta tiny rectangular box which says 'SONY' on it, funnily enough.
get yourself a cotton bud with some of this said 'rubbing alcohol' on 1 end of the bud - i used this tiny little yellow bottle of stuff which you use to clean cd's - this worked fine.
rub the laser eye in circular motions for about 10 seconds with the DRY side of the cotton bud first and then use the WET side with the alcohol on - circular motions for 20 seconds. go both clockwise and anti-clockwise... after this, use a clean DRY bud to clear off any excess alcohol and it should be cleaned.
whack the laser case on with the screws.. carefully place the big case back on - put all the screws back in their places and put the rubber and harder stops back in their places.
Also give the vents a little hoovering before seeing if your games work again

hope this helps