Make sure the cover isn’t on your lawn or anywhere where cleaner could run off and kill plants.

For routine cleanings, you should scrub only the top side of the cover with cleaner. Just rinse the bottom of the cover with water. Avoid products that contain bleach or alcohol, as these can wear away the cover’s layer of UV and mildew protectant. If you’re concerned about how chemical runoff might affect adjacent grass, you can use an eco-friendly vinyl cleaner. [4] X Research source

To keep your cover in the best condition, you should clean it once every one to three months. It’s best to condition the cover with a UV vinyl protectant after cleaning it. Be sure to apply the protectant before reattaching the cover to the tub.

If necessary, you can also use a solution of one part vinegar and one part water to spot clean bird droppings. To spot clean tree sap, rub a cloth with bit of olive oil over the affected area. [6] X Research source

Most covers are made of vinyl, but some are made of acrylic. There’s no need to apply a protectant to an acrylic hardcover.

You can also use saddle soap to condition your cover. [7] X Research source Avoid using petroleum-based products to condition your hot tub cover.

Protecting the cover from outdoor elements using a tarp can extend its life.

If you notice a persistent moldy smell, you might have an issue with your interior foam cores. If you have trouble finding a hidden zipper, check your product manual. You can also search online for your tub’s manufacturer and model number to download a digital copy.

If you find any tears or punctures in the plastic liners, use duct or packaging tape to repair them. Even if you don’t have to clean out a mold problem, you should inspect your foam cores every three to six months.

Use a soft bristled brush to gently scrub the interior of the vinyl cover and foam cores. Then use a garden hose to rinse them thoroughly. Avoid using a bleach solution near grass, bushes, trees, or other vegetation. If you’re concerned about runoff, look for an eco-friendly mold and mildew cleaner at a nearby home improvement or department store.   

Don’t leave the foam cores in direct sunlight to dry, or they might melt.

Like flipping a mattress, you should flip your foam cores twice a year to prevent sagging.