Decades ago, a full mailbox meant you had a lot of friends and family who wanted to keep in touch. Today, it means your address is logged into the credit card industry’s data base.

According to 41pounds.org, a nonprofit environmental Web site dedicated to combating the scourge of junk mail, 100 million trees are cut each year to produce the paper for those credit card, insurance and other unsolicited offers. The “41 pounds” refers to the estimated weight of a year’s worth of junk mail for one household.

Here are some other staggering numbers from the site: whoever is responsible for sorting through the mail wastes 70 hours a year dealing with 560 pieces of junk mail; 44 percent goes to the landfill or incinerator unopened; $320 million of local taxes are used to dispose of junk mail each year; California’s state and local governments spend $500,000 a year collecting and disposing of AOL’s direct mail disks alone; and transporting junk mail costs $550 million a year.

In addition to the waste of time and resources, those credit card come-ons are also prey for those who would steal your identity. According to a report by MSNBC, 4 million fraudulent credit card accounts are opened each year in the U.S., and 400,000 are tied to the unsolicited mail offers.

Just as entering your telephone number on the federal “Do Not Call” registry put the kibosh on telemarketers interrupting your dinner, there is a way stem the tide of junk mail.

An excerpt from the book “Scam-Proof Your Life” by Sid Kirchheimer, posted on MSNBC’s Web site includes a step-by-step process for opting out of junk mail. He writes: “Call 888-567-8688 (888-5-OPT-OUT) from your home telephone (so it can be checked against an address database) or visit www.optoutprescreen.com to stop preapproved credit card and insurance offers from reaching you by mail or phone. (The source for these come-ons is lists sold to companies by the credit-reporting agencies Equifax, Experian, TransUnion, and the smaller Innovis.) If you call, you’ll get an automated voice-response system that requests your name, telephone number and Social Security number; don’t worry, they have it already as part of your credit history. Whether you call or go online, you can opt out for five years or permanently; if you choose the latter, you’ll be sent an additional form in the mail that must be mailed back. Your opt-out ‘vote’ goes into effect in about five business days, but do not expect to see a noticeable reduction for roughly one month.”

Good advice for those beleaguered by the deluge of junk mail.