We have found a shoebox full of approximately $100,000 worth of Series E bonds under the bed of our aging mother. A lot of them matured 20 years ago. Can you advise me on the best way to cash these bonds in? Can you tell me what the penalty and interest would be that we would have to pay if these bonds are cashed in today? Tom's response First, get a Power of Attorney from your mother that specifically mentions Savings Bonds so you can begin to deal with this. Your mom probably doesn't want to know this, but if these bonds had been cashed, the taxes paid, and new Saving Bonds purchased when these matured, she'd have over $300,000 now. I'm not trying to make anyone feel bad - I'm just trying to make it clear to everyone that you should redeem bonds that aren't paying interest as soon as you can, pay the taxes, and reinvest the money. The IRS isn't interested in an amended return from 20 years ago. Given the amount of money involved here, I think it would be worth it to you to pay a tax accountant or attorney to help you sort this out. There's a form you can use to list all the bonds so you don't have to sign them all. Click here for a web page about savings bonds that includes links to both the forms I've mentioned here.