Gently scrape off loose adhesive with a plastic scraper or old credit card
Soften the adhesive with warm soapy water and a sponge
Apply rubbing alcohol to a cloth and dab the residue
Use white vinegar on a cloth for stubborn adhesive
Try a small amount of adhesive remover or citrus-based cleaner
Let the cleaner sit briefly, then wipe away the residue
Repeat as needed until the wall is clean
Wipe the area with clean water and dry it
Test any cleaner on a small hidden spot first
Avoid abrasive tools that can damage the wall finish