I had a passport issued when I was 13 yrs old (in 1984), which became expired. In 2004, I had applied and got another passport without surrendering the previous one. The second passport too has expired. I have not travelled anywhere outside the country. Can I now return both these passports and apply for a new one again?
The old expired passport is one of the documents you will need (in addition to proof of address, Non-ECR proof if applicable, and possibly other documents) in order to apply for reissue of your passport. India normally returns the expired passports after your reissue is processed, so it's expected that you would have expired passports in your possession.
The returned passport will have a cancelled stamp and the ID page's corner will be cut to mark as invalid for automated passport machines.