How do I clean bathroom knobs to make them look less dull?

Paper towel saturated with vinegar. Dry cloth to buff and polish.

Take it to the paint dept. at the home improvement store and ask for their suggestions on paints/sprays to upgrade it.

Clean the holder well and then add just a drop or two of whatever cooking oil you might have in your kitchen to a paper towel. Rub that all over the TP holder and it'll shine!

We painted the knobs on our bathroom vanity....brass to silver. Worked for about a year and then started rubbing off.

thank ya'll

Here is how I clean mine https://chascrazycreations.com/clean-bathroom-natural-products/