Consumers have been warned for years about websites, flea markets and others selling counterfeit Chanel handbags, NBA jerseys, MAC cosmetics and, yes, even fake Apple chargers.

So, now as we move closer to Aug. 21's eclipse mania, it should be no surprise that we're being warned about pirated eclipse glasses that could be unsafe for watching the coast-to-coast solar eclipse. Millions of people are likely to be watching either a partial eclipse that day or the total eclipse in other parts of the country.

These "eclipse glasses" are cheap — maybe $1 or $2 each — but if you use bad glasses you risk burning your retina. Injuries might be temporary or longer-term. Improper viewing of the sun during an eclipse could cause "eclipse blindness" or retinal burns.

Special solar filters enable you to look at the partially eclipsed sun. Typically, consumers should look for the stamp of approval from the International Organization for Standardization or ISO and a label indicating that the product meets the ISO 12312-2 international safety standard.

But it's important to realize that the con artists are printing the ISO logo and certification label on sham solar glasses and handheld solar viewers.

"Don't just search for eclipse glasses on the Internet and buy whatever comes up," warned Rick Fienberg, press officer for the American Astronomical Society.

Many people might be tempted to do just that if they get frustrated shopping. Early in August, it was far easier to find fidget spinners and flexible expandable garden hoses at many stores than eclipse glasses. Many clerks hadn't even heard of "eclipse glasses." One clerk wondered out loud where you'd ever find those.

Check out more nationwide coverage at: solareclipse.usatoday.com.

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But some big name retailers are expected to offer these glasses in stores.

The American Astronomical Society has an online list of reputable vendors at its website. See www.eclipse.aas.org/resources/solar-filters.

Chains selling the ISO-compliant safe eclipse glasses or handheld viewers include Kroger, Walmart, REI, Toys "R" Us, Lowe's, Best Buy and 7-Eleven.

Dozens of Walmart Supercenters are set to be selling the glasses and Walmart's "Get Eclipsed" booklets.

Walmart has a "Get Eclipsed" guidebook with solar glasses included for $3.47 at its stores. The glasses alone are $1. Many stores have a dedicated "Get Eclipsed" display.

Walmart, like other retailers, will be promoting eclipse-themed products — like Luna bars, Moon Pies, Sun Chips, Eclipse gum, and the like for stellar picnics.

"We're definitely seeing sales heat up for certified solar viewing glasses at thousands of Walmart stores nationwide, the hottest tracking in those states along the eclipse totality path from Oregon all the way to South Carolina," said Meggan Kring, a Walmart spokesperson, in an e-mail.

Many libraries across the country have been offering free glasses. See www.starnetlibraries.org. More than 7,000 libraries nationwide are hosting eclipse related events. Many libraries have received glasses through a program with the Space Science Institute's National Center for Interactive Learning and STARnet for Libraries.

Elizabeth Delaney, staff attorney in the FTC's division of advertising practices, noted that consumers might not realize that their eyes have been harmed immediately by bad eclipse glasses. In some cases, she said, you can damage your retina and not feel it.

People shouldn't use old glasses that they might have purchased in the past, either. "Glasses that are more than 3 years old, or are wrinkled or scratched, won’t protect your eyes," the FTC said.

Obviously, you don't want to look directly at the sun through old 3D glasses from the movies, regular sunglasses, a telescope or binoculars.

Fienberg said consumers might find the counterfeit glasses online or even in unexpected spots, like a smaller corner store. He found some at a small general store in New Hampshire for $2 a pair. He noted that the glasses were labeled with the name and address of American Paper Optics, one of the leading manufacturers of genuinely safe solar viewers.

But he said the lenses were rectangular, not more oval like the ones made by American Paper Optics. The questionable product had filters that were black on both sides. But the filters by American Paper Optics are coated with metal on one side.

Other clues: You shouldn't be able to see anything through a safe solar filter except the sun or something comparably bright, such as the filament of an incandescent lightbulb. If you glance at the sun through a solar filter and find it uncomfortably bright or out of focus, your viewer is not good.

Contact Susan Tompor: stompor@freepress.com or 313-222-8876. Follow Susan on Twitter @Tompor.