SAN FRANCISCO (KRON) – Have you recently received unwanted packages on your doorstep from Amazon that you don’t remember ordering?

They could be part of an ongoing scheme, the Better Business Bureau warns.

It’s called a “brushing scam,” according to authorities, and it happens when people receive unsolicited items from a seller who then posts fake customer reviews to boost sales.

What is a ‘brushing’ scheme?

The BBB says even though this isn’t a new scheme, it wants to remind people that getting free boxes of merchandise from Amazon or other companies isn’t always a good thing.

“You are not the one who hit the jackpot. A scam company is the real winner,” the BBB said in a news release on Monday.

The BBB says some examples of what people have found in the packages – which are usually very light – include flashlights and Bluetooth speakers.

If you receive a mystery package in the mail, the BBB advises you to notify the retailer. It also suggests changing passwords and keeping an eye on your credit reports and credit card statements.

Can you keep the free merch?

According to the Federal Trade Commission, you technically can, as you have “a legal right to keep it as a free gift.”

Moving forward, the FTC advises you to be cautious if you sign up in a sweepstakes or contest or click on ads marketing “free” or “trial” products.

For more help, you can contact your state or local consumer protection office.