White residue sign of Leaking Caps?

[clm811]

I got some surplus NOS electrolytic caps recently, and one or two in the batch have a white residue around the little rubber plug on top of the can...

Is this something to be concerned about(i.e are the caps "bad"), or is this white stuff benign(and just be wiped off and ignored)? The rubber plugs have not "popped up", which I understand is a sign of a bad cap.

I paid over $15 each for these "new" (old stock) capacitors.

The photo shows the white reside, which I partially wiped off with my finger to see if it was paint or something else.

TIA

-Chas

[SY]

Lesson learned- don't buy old electrolytics. Besides having a short shelf life, the technology is hugely better now. Those are an explosion waiting to happen, and I wouldn't even think about using any from that batch, even the ones that aren't showing the white residue- yet.

Sorry, wish I had better news.

[clm811]

The seller is an established surplus dealer in the U.S. and the listing on their website said:"New"

I wrote them and advised of the problem, with a picture like the above.

Now I just visited the webpage and they are now shown "out of stock"

I hope they will take them back and refund my money...

-Chas

[regiregi22]

What happened in the end? any news from the distributor?

[clm811]

What happened in the end? any news from the distributor?

The retailer checked and responded that he checked the remaining stock and while some pieces have the white residue, they "tested ok" and he offered to replace the two pieces in question.

They've subsequently changed their web page to show it as "Out of Stock" .

The replacements look fine and I'm totally satisfied with their response, which was prompt and polite.

p.s. I understand that these NOS pieces were manufactured approximately 7 years ago.