It looked like you used some gun cleaner or gun oil that was eating away the finish on the slide.

What solvents have you used on the gun? Whatever it was the finish didn't like it.

I use Smith & Wesson advance gun oil on all my guns. I've been using it for a few years and haven't had this happen on anything else. No problems on my beretta, glock, walther (well walther up until now). I find it odd that it would be the cause since its the same company that made made both the gun and oil. But I really don't know what else it could be, since this is the only thing I put on it.

I don't think it would be the gun oil either. How and where do you store the gun? Do you store it in a leather holster? It looks like it's been exposed to something harsh or the manufacturer flubbed on the finisning job. If it were me I'd degrease it and give it a going over with a Q-tip and Birchwood /Casey Super Blue, at least it will look better than it does now.

The slide on a Walther P22 is not steel, it's zinc or a zinc alloy of some sort. Looks to me like the finish is chipped off, and you're seeing the bare metal.

Most of the slides on new guns are investment casted. its a cheaper way to make guns instead of machining them on a CNC lath and they anodized the finishes instead of chrome or bluing.

The hard chemicals in the cleaners you are using are taking off the finish. Best you can do is send it to someone and have it refinished or just shoot it and have fun

Anodized aluminum turns white from the salt in your hands. It happens and I found no way to avoid it other than a clear coat of lacquer. This happened on early Ruger single actions. My solution was to install steel grip frames, not an option in your case, though.

Bob Wright

The odd thing is that I haven't used this gun in months. So I haven't touched it or put anything on it for a while now. It would just sit in my night stand.

just wanted to update... it has now gone away and is back to normal :/ if it was the actual finish wouldn't that not go away?

Originally Posted by MLB

The slide on a Walther P22 is not steel, it's zinc or a zinc alloy of some sort. Looks to me like the finish is chipped off, and you're seeing the bare metal.

Bingo! I wondered how many post I would have to read until someone posted what the slides are actually made of on the P-22. Basically its the same material (Zimac-Spelling?) that the slide on my Hi Point is made of.

Zinc and aluminum oxidation are both white. Finish might've been flawed allowing the metal to oxidize. I think allowing to sit in the nightstand (I'm assuming without some sort of descant) let moisture in the air to come in contact with the metal. You may have just polished off the rest of the oxidation down to clean metal. Just wiping it down left it there after it dried.

Originally Posted by Bob Wright

Anodized aluminum turns white from the salt in your hands. It happens and I found no way to avoid it other than a clear coat of lacquer...

Originally Posted by NewinSD

Zinc and aluminum oxidation are both white. Finish might've been flawed allowing the metal to oxidize. I think allowing to sit in the nightstand (I'm assuming without some sort of descant) let moisture in the air to come in contact with the metal. You may have just polished off the rest of the oxidation down to clean metal. Just wiping it down left it there after it dried.

Give each man a cigar!

I have the exact same problem with the aluminum frame of my Star PD, at the upper back of its grip where it gets the most wear.
The fix: Polishing carefully down to bare metal, and re-coating it with a durable coating. Mr. Wright suggests lacquer, but I have had better luck with semi-gloss, black epoxy paint. A bake-on coating would also do the trick.
(See Brownells at: http://www.brownells.com/)