I purchased a used Canon Powershot A1100 IS camera online. When I received it in the mail it had a very strange sticky substance that looked like a thin film.

It resisted attempts at cleaning. Water, water + soap, baking soda + vinegar, baking soda only, vinegar only and rubbing alcohol all did not resolve the issue. Only vigorous scrubbing kind of helped.

In addition I could not get it off my hands at all even after about 10 hand washing attempts and soaking my hands in soap and water. After my hands dried the areas where my hands touched the camera were still sticky. The only thing that helps was after it dried rubbing my hands with a paper towel. When wet it was not sticky then when it dried it came back.

The battery terminal was completely corroded with a blue color and it seems like there was some but possibly less of the substance internally. Battery terminal This is part of the battery door. It is used to complete the circuit between the two AA batteries that the camera takes.

Scraping away the blue crystal only results in more of what you can already see in the picture. Metal that looks grey in some places and brown/red in others.

The closest thing I can think of is petroleum jelly but I can't be sure that, that is it. I don't have any and don't work with it much so I can't compare what it looks like.

Based on my description do you have any possible ideas on what it is?

If you do have something that matches these symptoms would you happen to know what its toxicity is and proper cleanup procedure?

Also in general how should one handle touching something they don't have knowledge of but that could be dangerous and when hand-washing is not working/removing it.

Thank you in advance for your questions and answers.

  • $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – user7951
    Commented Sep 20, 2019 at 17:56

2 Answers 2


After the lengthy back and forth perhaps an official answer is due: the blue salt deposit on the camera battery holder door is most likely copper(II) hydroxide by reaction of leaked alkaline battery electrolyte (likely $\ce{KOH}$) with copper metal in the battery door contact. It could possibly also consist of copper(II) carbonate hydroxide formed by reaction of the copper(II) hydroxide with carbon dioxide, but the deep blue rather than green color in the picture suggests it is the previous. Copper hydroxide is regarded as moderately hazardous, but you are unlikely to be at risk unless you ingest it. Feel free to consult a MSDS for this compound (such as here) for more information.

The sticky substance coating the camera is possibly a degradation product of plastic components in the camera housing. It is not likely to be toxic unless ingested or if you are in contact with it persistently.

Without more information about how the camera was maintained it is difficult to say much more.

  • 1
    $\begingroup$ I agree with your final conclusion. This logically explains everything I noticed. Also the plastic explanation makes more than rubber which I thought it was previously. $\endgroup$ Commented Sep 21, 2019 at 2:19

I agree with @BuckThorn on the blue corrosion but I'd like to address the sticky substance. If it is in fact a degradation product of the plastic or some other substance being exuded by the plastic, I've had good luck removing these with oil-based cleaning agents. None of the cleaning products you mentioned will help very much in removing a nonpolar organic substance.

Try rubbing a small area of stickiness with a cloth moistened in WD-40, Goof Off, Goo Gone or any similar oil based cleaning product. These should work on sticky fingers too. If one of these removes the stickiness on the camera without damaging the finish, you can carefully clean the rest of the camera.

  • $\begingroup$ Mineral spirits (conventional paint thinner) might be a better choice than the other products mentioned, which are more likely to damage plastic. $\endgroup$ Commented Sep 22, 2019 at 1:16

Not the answer you're looking for? Browse other questions tagged or ask your own question.