You saw them on television day after day during news coverage of hurricanes Harvey and Irma, and you see them almost anytime there’s a flash flood somewhere.

We’re referring to cars and trucks submerged in floodwaters up to their roofs.

Now, after the hurricanes, scammers have cleaned up hundreds of thousands of these totaled vehicles and will try to sell them to the unsuspecting.

Carfax, a company that provides vehicle history reports, says about half of cars damaged in floods later return to the road. That means hundreds of thousands of Americans are “getting duped out of thousands of dollars with a vehicle that’s literally rotting from the inside out,” says Carfax spokesman Christopher Basso. His company estimates there are about 325,000 flood-damaged vehicles on the road today from past storms, spread across all states.

How does this happen? Here are three typical ways:

1. Auctions. After an insurance company places a flood or salvage title on a vehicle, it can be auctioned off legally and then salvaged and cleaned up by a buyer, who may put it back up for sale to consumers.

2. For sale by owner. Owners lacking adequate insurance often scrub the vehicle themselves, perhaps replacing carpet or upholstery before selling it.

3. Forged documentation. Unscrupulous sellers might tamper with title records to trick buyers into believing a car is in good condition.

Flood victims who need to find transportation quickly often buy such cars if their insurance doesn’t provide them a free rental car. But consumers should take their time and apply due diligence, says AAA car-buying expert David Bennett. “Try not to rush into a decision, and make sure you’re buying a car that fits your needs,” he says.

How can you avoid buying a flood-damaged vehicle? Here are eight tips:

1. Check the vehicle history report. If insurers have covered flood damage on a car, the history report will note that the car has been salvaged. Be sure to check Carfax for those records.

2. Hire a mechanic to inspect the car carefully before you buy it.

3. Make sure the car passes the smell test. Musty smells indicate the presence of moisture, which may have come from floodwaters.

4. Pull back the carpet in several places. Look for signs of water or mud. If the carpet or upholstery has clearly been replaced, walk away.

5. Make sure the power locks and windows work. Check other electrical components too. If they don’t work, it may mean that water has caused electrical damage.

6. Check headlights and taillights for water. If there’s moisture in them, the vehicle might have been underwater.

7. Inspect for corrosion all over — although it might take time for rust to show up.

8. Don’t take the seller’s word. Always take the vehicle for a full test drive at full highway speeds.