You can use a paper towel (in the bathroom) or a tissue if you have a nearby source of them. I think using your sleeve (for door handles) or your knuckle (for buttons) is still better than using your hand, because you are much less likely to use your knuckle/sleeve to later touch your face / keyboard / phone. (However, using your hand seems better than using your sleeve if you are about to wash or sanitize your hands.)
You can use a paper towel (in the bathroom) or a tissue if you have a nearby source of them. I think using your sleeve (for door handles) or your knuckle (for buttons) is still better than using your hand, because you are much less likely to use your knuckle/sleeve to later touch your face / keyboard / phone. (However, using your hand seems better than using your sleeve if you are about to wash or sanitize your hands.)