Few things are more distracting while driving in the rain than a wiper blade that leaves a trail of lines across the glass. Whether it is a single streak right at eye level or a series of arcs that blur your view, these marks reduce visibility and can make night driving dangerous. Fortunately, fixing the problem is usually straightforward.

The key to solving wiper streaks is to work through the potential causes in order, starting with the simplest solution and moving toward the more complex. Here is a step-by-step guide to clearing up those marks.

Step 1: Clean the Wiper Blades Thoroughly

Often, the marks are not caused by a broken blade, but by dirt riding on the rubber. Over time, wiper blades collect a layer of road grime, bug residue, tree sap, and microscopic debris. This buildup creates hard spots that scratch or smear water rather than clearing it.

• What to do: Lift the wiper arms away from the windshield. Take a clean cloth or paper towel and soak it in windshield washer fluid or rubbing alcohol. Pinch the rubber blade between your fingers and run the cloth firmly along the entire length of the rubber. Repeat until the cloth no longer picks up black residue or feels gritty.

• Why it works: This removes the abrasive particles embedded in the rubber edge, restoring the blade's ability to make clean contact with the glass.

Step 2: Deep Clean the Windshield

If the blades are clean but the marks persist, the glass itself may be contaminated. Wax from a recent car wash, oil from the road, or tree sap can bond to the windshield. When the wiper passes over these spots, it pushes water around them, creating streaks and patches.

• What to do: Wash the windshield with a dedicated automotive glass cleaner. For stubborn contamination, use a mixture of rubbing alcohol and water or a few drops of dish soap in warm water. Scrub vigorously with a microfiber cloth or sponge. Rinse thoroughly.

• For tough cases: If the glass still feels rough or looks hazy, use an automotive clay bar with lubricant. Glide the clay across the wet glass. You will feel it pull off invisible contaminants that water alone cannot remove.

Step 3: Inspect the Rubber Edge

After cleaning, look closely at the wiper blade's rubber edge. Run your fingernail gently along it. Do you feel any nicks, chunks missing, or a rough texture? If the rubber is torn or has a distinct notch, that notch is carving a line into the water film every time the blade passes.

• What to do: If the rubber is visibly damaged, the blade must be replaced. There is no way to repair torn rubber.

Step 4: Check for a Bent Frame

If your vehicle uses traditional bracket-style wiper blades, inspect the metal frame. Look at the blade from the side while it is resting on the glass. Does it follow the curve of the windshield evenly, or is there a spot where the frame appears kinked or bent?

• What to do: A bent frame prevents the rubber from sitting flat against the glass. You may be able to gently bend it back with pliers, but this is rarely a permanent fix. Replacing the entire blade is the more reliable option.

Step 5: Verify the Blade Size

Using the wrong size wiper blade is a common mistake. If the blade is too long, the ends may press too hard while the center lifts, creating a large unwiped area. If it is too short, it will leave a curved mark at the top of its arc where the glass curvature changes.

• What to do: Consult your owner's manual to confirm the correct blade length for your vehicle. If you have the wrong size, purchase the correct replacement.

Step 6: Replace the Blades

If you have cleaned everything and inspected for damage but the marks remain, the blades are simply too old. Wiper blades are consumable items. Exposure to sun, ozone, and weather hardens the rubber over time, making it stiff and less effective. A hardened blade cannot conform to the glass and will leave streaks across its entire path.

• What to do: Purchase a new set of high-quality wiper blades. As a general rule, blades should be replaced every six to twelve months, depending on your climate and usage.

Summary Checklist

If your wipers leave marks, follow this order:

1. Clean the blades with alcohol or washer fluid.

2. Clean the glass with a degreaser or clay bar.

3. Inspect the rubber for nicks or hardening.

4. Check the frame for bends.

5. Confirm the size is correct for your car.

6. Replace the blades if all else fails.

By systematically eliminating each potential cause, you can identify the source of the streaks and restore clear vision in wet weather.