# What happens if I touch the lens? **URL:** \ **Category:** Factual Questions\ **Created:** [January 5, 2003, 8:32am UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754 "2003-01-05T08:32:19Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![I\_can\_t\_believe\_that\_s\_butter](https://avatars.discourse-cdn.com/v4/letter/i/8edcca/32.png) [@I\_can\_t\_believe\_that\_s\_butter](https://boards.straightdope.com/u/I_can_t_believe_that_s_butter)\ **Post date:** [January 5, 2003, 8:32am UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754/1 "2003-01-05T08:32:19Z")
Is this an efficient way of “loving-up” my CD player, or is it repairable? ---
**Author:** ![Ice\_Wolf](https://avatars.discourse-cdn.com/v4/letter/i/dfb087/32.png) [@Ice\_Wolf](https://boards.straightdope.com/u/Ice_Wolf)\ **Post date:** [January 5, 2003, 8:50am UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754/2 "2003-01-05T08:50:33Z")
Everywhere, they say “don’t touch the lens”. I’d say it was a definite no-no, **Joe K**. Try cleaning it anyway: > [@](#): > > Don’t touch the lens with your finger or you will complicate the problem. Take a cotton swab and use a mild glass cleaner. Moisten the swab slightly. Shake off any excess. Now gently, and again I say gently, clean the lens with a circular motion. It doesn’t take much to accomplish this so take it easy. Then use a dry swab to clean off any residue. Try the player again and if skipping is still a problem, take the unit in for service. [From this page.](http://elliottelectronics.com/tech.html) ---
**Author:** ![I\_can\_t\_believe\_that\_s\_butter](https://avatars.discourse-cdn.com/v4/letter/i/8edcca/32.png) [@I\_can\_t\_believe\_that\_s\_butter](https://boards.straightdope.com/u/I_can_t_believe_that_s_butter)\ **Post date:** [January 5, 2003, 9:10am UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754/3 "2003-01-05T09:10:32Z")
Mind, I didn’t touch it _yet_, I’m curious just in case I encounter this threat of a touched lens, which is somewhat realistic with Discman-type players. ---
**Author:** ![Ice\_Wolf](https://avatars.discourse-cdn.com/v4/letter/i/dfb087/32.png) [@Ice\_Wolf](https://boards.straightdope.com/u/Ice_Wolf)\ **Post date:** [January 5, 2003, 9:17am UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754/4 "2003-01-05T09:17:27Z")
Well, then – _ **don’t** _! 🙂 ---
**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\ **Post date:** [January 5, 2003, 9:18am UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754/5 "2003-01-05T09:18:27Z")
If you touch it, you’ll leave an oily fingerprint on it. The oily fingerprint may prevent the laser focussing correctly on the disc. Each time you clean off the fingerprints, you risk scratching the lens. Best to avoid it. ---
**Author:** ![Astroboy14](https://avatars.discourse-cdn.com/v4/letter/a/df705f/32.png) [@Astroboy14](https://boards.straightdope.com/u/Astroboy14)\ **Post date:** [January 5, 2003, 10:53am UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754/6 "2003-01-05T10:53:20Z")
> [@](#): > > \*Originally posted by Desmostylus \* > \*\*If you touch it, you’ll leave an oily fingerprint on it. The oily fingerprint may prevent the laser focussing correctly on the disc. Each time you clean off the fingerprints, you risk scratching the lens. Best to avoid it. \*\* So… I’m guessing it was wrong of me to spit on the lens and polish it with the elbow of my shirt? Rats! ---
**Author:** ![Bryan\_Ekers](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bryan_ekers/32/183_2.png) [@Bryan\_Ekers](https://boards.straightdope.com/u/Bryan_Ekers)\ **Post date:** [January 5, 2003, 11:08am UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754/7 "2003-01-05T11:08:45Z")
> [@](#): > > \*Originally posted by Astroboy14 \* > \*\*So… I’m guessing it was wrong of me to spit on the lens and polish it with the elbow of my shirt? > > Rats! \*\* I wouldn’t run it through the dishwasher, either. ---
**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\ **Post date:** [January 5, 2003, 11:28am UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754/8 "2003-01-05T11:28:03Z")
MIKE: Must have gone wrong somewhere. VYVYAN: Oh God! MIKE: Maybe you shouldn’t have poured all of that washing-up liquid in it. VYVYAN: But it says here, Michael look, “Ensure machine is clean, and free from dust”! MIKE: Yeah, but it don’t say, “Ensure the machine is full of washing-up liquid”! VYVYAN: No, but it doesn’t say, “Ensure the machine isn’t full of washing-up liquid”! MIKE: Well, it wouldn’t would it! I mean, it doesn’t say, “Ensure you don’t chop up your video machine with an axe, put all the bits in a plastic bag, and bung 'em down the lavatory”! VYVYAN: Doesn’t it? Well maybe that’s what’s going wrong! [picks it up as if to start following these new instructions] MIKE: [yelling] VYV! Put it down! Put it down! That’s worth 500 pounds! I’m minding it for Harry the Bastard! ---
**Author:** ![Ice\_Wolf](https://avatars.discourse-cdn.com/v4/letter/i/dfb087/32.png) [@Ice\_Wolf](https://boards.straightdope.com/u/Ice_Wolf)\ **Post date:** [January 5, 2003, 11:33am UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754/9 "2003-01-05T11:33:50Z")
Heh, heh, heh. Oh, you have _style_, **Desmostylus**! 😃 ---
**Author:** ![Desmostylus](https://avatars.discourse-cdn.com/v4/letter/d/c57346/32.png) [@Desmostylus](https://boards.straightdope.com/u/Desmostylus)\ **Post date:** [January 5, 2003, 12:17pm UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754/10 "2003-01-05T12:17:01Z")
Well, thankyou, **Ice Wolf**. 🙂 ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [January 5, 2003, 6:24pm UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754/11 "2003-01-05T18:24:36Z")
1. Do _not_ use a cotton swab. The lint from the swab will remain on the lens and it won’t be truly clean. Use a foam swab. (Cheap at Radio Shack.) Also don’t use standard drug store rubbing alchohols which contain “extras” that will also dirty the lens. Use lens cleaning rated solutions. (Also available at RS and such stores.) Don’t try to blow off dirt using a can of compressed air. (Too forceful.) The “Lens cleaning discs” sold at stores are at best useless. (Although some have a good quality solution for cleaning by hand.) 2. Oil from your finger is not just bad since oil messes up the optics, it also attracts and holds dust particles. That’s why something that was touched a long time ago (and forgotten) later develops dirty lens problems. This is quite noticable if you have idiots touching computer screens. First the oil then the dirt. Read all about such stuff at the [Repair FAQ homepage.](http://www.repairfaq.org). ---
**Author:** ![MadScientistMatt](https://avatars.discourse-cdn.com/v4/letter/m/bc8723/32.png) [@MadScientistMatt](https://boards.straightdope.com/u/MadScientistMatt)\ **Post date:** [January 5, 2003, 8:21pm UTC](https://boards.straightdope.com/t/what-happens-if-i-touch-the-lens/146754/12 "2003-01-05T20:21:01Z")
I’d probably try using lens tissue (I think you can get it at photography stores, but I’m not sure) and acetone or denatured alchohol. That’s what I use to clean on industrial laser lenses at work, which can shatter if any dirt or oil sticks to them.