Thank you for contacting Koss Stereophones....so, for shipping there plus $7 plus whatever my bank charges me for writing a cheque, they'll repair or replace them. I can buy a new pair for $20 from their web site, but I'm not sure what shipping is.
Stereophones that were purchased after July of 1989 are covered by our No-Questions-Asked Lifetime warranty.
Please send your stereophones to our Corporation and we will repair or replace them in accordance with our Limited Lifetime Warranty.
I wonder if they'll actually repair them, or if they'll send me a new pair? (Given that they also need new foam covers, and they sell those for $5, it's probably worth it to buy a new pair rather than get the old ones repaired.)
I don't have the dated receipt any more (I think), but they don't ask for the receipt.
If it were you, what would you do?