There are several ways to clean downspouts, and you can choose the right one depending on the situation and your personal preference. Here are a few ways to effectively clean downspouts:

Baking soda and salt method. Pour baking soda in a container, add salt in a one-to-two ratio, stir well, and spread the mixture down the drain, followed by pouring in warm water to help dissolve grease and stains.

Laundry Detergent Method. Pour laundry detergent down the drain and add hot water to dissolve grease and clear the clog. This method is simple and efficient.

White vinegar and baking soda method. Pour baking soda around the drain opening, then pour in white vinegar, wait 10 minutes, and then rinse with hot water to remove gunk and grease.

Caustic soda method. Place a caustic soda block in the floor drain, then pour hot water to melt it. This method is suitable for severe clogging, but be aware that caustic soda is corrosive.

Pipe Unclogging Agent. There are commercially available pipe unclogging agents that can easily dissolve clogs, but you need to follow the product instructions when using them.

Physical methods. Use drain snakes or homemade tools (e.g., spiked tools made from straws) to physically clear clogs.

Regular Prevention. Clogs can be prevented by regularly flushing downspouts with hot water.

Each method has its advantages and disadvantages, and the most appropriate method can be selected based on the situation and available resources. Ensure safety before using any cleaners or physical tools, especially when using caustic soda and pipe unblockers, and handle with care to avoid contact with skin or eyes.