A dampened cotton swab is helpful for cleaning on and around the buttons.
I had a similar issue and I used warm soapy water and a sponge. Popping the buttons off and scrubbing them gently did the trick, just don't go at it too hard or the paint will come off.
Dust and Wipe: Use a dry cloth to dust off the switch and surrounding area. For light stains, you can use a cloth slightly dampened with water or a mild cleaner. Avoid using excessive moisture. Clean the Switch: If necessary, use a cotton swab lightly moistened with rubbing alcohol to clean around the switch itself.
Use isopropyl alcohol, highest percentage you can find. The alcohol evaporates quickly and takes a lot of the water with it, making it safer for your phone. You should still use as little as possible.
Put some rubbing alcohol on a microfiber cloth and wipe down the remote. When the stickiness is gone, dry the remote with a clean towel or cloth.
Cleaning Products for Remotes
It includes Clorox cleaner and bleach products, Lysol disinfectants, Purell sanitizers, and Zep disinfectants and cleaners. A household bleach or alcohol solution can also be used, the CDC says.
Do not use rubbing alcohol, paper towels, compressed air, dish soap or vinegar. All of these can damage your phone: Paper towels can scratch your screen, and vinegar could damage its coating. Do not use hand sanitizer on your phone screen, but do sanitize your hands before touching your phone.
Check and clean the Power button
Inspect the Power button for any damage. Check for debris or dirt around the button. Clean it with a microfiber cloth or a cotton swab dipped in a bit of rubbing alcohol.
For tarnished brass or copper: in a plastic or glass container, dilute 1 Tbsp of a weak acid (vinegar or lemon juice) in 4 cups water and add 1 tsp of salt. Add the items and let soak for a few minutes. Transfer to a second container and rinse thoroughly. Rub dry with a soft cloth like an old t-shirt.
Isopropyl Alcohol: Use a small amount of isopropyl alcohol on a microfiber cloth to rub away the residue. This method is safe for most electronic surfaces, but avoid getting liquid into any ports or openings.
Dampen the cotton swab with rubbing alcohol, dabbing off any excess. Rub the cotton swab around the sticky button. Be sure to clean inside the crevices. Once you've cleaned around the button as much as possible, press it a bunch of times to work the rubbing alcohol into the crevices and loosen any debris left behind.
Using a 70 percent isopropyl alcohol wipe, 75 percent ethyl alcohol wipe, or Clorox Disinfecting Wipes, you may gently wipe the exterior surfaces of your iPhone. Don't use products containing bleach or hydrogen peroxide. Avoid getting moisture in any openings, and don't submerge your iPhone in any cleaning agents.
70% isopropyl alcohol wipe: Apple, Samsung, and Google all recommend using isopropyl alcohol–based cleaning wipes on their devices. Apple also says you can use 75% ethyl alcohol wipes or Clorox Disinfecting Wipes.
If your phone's power button isn't clicking properly, it could be due to dirt, wear and tear, physical damage, moisture damage, or a manufacturing defect. Try cleaning it, consider trying Fixtops AI which is designed to diagnose phone power button problems and also offer guidance on potential fixes.
Don't clean your device with window cleaners, household cleaners, compressed air, aerosol sprays, solvents, ammonia, or abrasives containing hydrogen peroxide. Don't use bleach or submerge your device in any cleaning agents.
Keep Isopropyl Alcohol out of confined spaces, such as sewers, because of the possibility of an explosion. DO NOT wash into sewer. Isopropyl Alcohol is dangerous to aquatic life at high concentrations.
While it is safe to use disinfectant wipes on many devices, keep in mind that those containing alcohol, bleach or vinegar may wear down the protective coating on a smartphone's screen.
Isopropyl alcohol evaporates quickly and it's relatively non-toxic. Isopropyl alcohol removes oils, adhesives, fingerprints, soldering flux and other contaminants, making it ideal for cleaning electronics.
The main difference between isopropyl alcohol and rubbing alcohol is the concentration. The concentration of isopropyl alcohol is 100%, while the concentration of rubbing alcohol is less because of the addition of water. Otherwise, the two liquids have similar properties.
For electronic printed circuit board (PCB) assembly, you will find isopropyl alcohol being used either to clean flux residues from recently soldered circuit boards, or in PCB repair and rework. IPA is also used to remove solder paste or adhesive from SMT stencils.