Cleaning a sticky DSLR lens

Question

I was on vacation recently and some coke accidentally splattered on one of my DSLR lenses. It was dark and I was pushing a stroller, so I didn't see what was going on until it was too late.

I cleaned off the coke from the outside of my lens, but now the focus ring sticks and is hard to move. Everything else still appears to work fine. How should I go about fixing this?

I'm not afraid to open it up and clean it (it's just the relatively inexpensive 18-55mm kit lens that came with my Pentax K200D, and if I wreck the lens, it's already essentially unusable in its sticky state), but I thought I would ask here to see if anyone has any thoughts/ideas.

Answer 1

First of all, my first suggestion is to have a professional cleaning...However, if the cost is prohibitive, this is my second:

I haven't tried it on camera equipment, but I have used 99% isopropyl alcohol to clean computer equipment. This is very similar to rubbing alcohol, but it is higher purity. A typical rubbing alcohol is about 60-70% pure, which means that there can be a lot of water/additives that will not help in the cleaning process, and may leave a residue after cleaning.

My main concern with this approach would be that the alcohol could clean the lens too well, removing some of the coatings that are added to reduce glare. From the sounds of it, that risk isn't too much of a problem in your situation though, as I'd rather have a lens with the possibility of bad coatings than a lens that doesn't focus well.

I would pour a small amount of the alcohol over the areas that are sticky, then gently wipe the excess off with a microfiber cloth. After giving it a little time to evaporate, try the rings, and if they are still sticky, repeat the process.