Is it foam? Maybe a soft bristle new toothbrush little kids if you need to get in tiny spots.
What kind of fish in the tank? Maybe you could get a live cleaner, like a Mystery snail, or a couple Nerite snails? With consideration in what is already living in the tank.
Then there is the lighting as a possible way to reduce algae.
New to FW fish? First tank in a long time or EVER??? Need some info on keeping fish?
Start here - Aquarium Advice Article
FW Favorites right now Clown Loaches, any shrimp - SW Vase Red Mangroves