What's the best way to apply sunscreen to your scalp without it getting greasy?

Use a powder sunscreen (brush-on or spray) or a sunscreen stick. Powder sunscreens are mattifying mineral SPF that absorb oil, so your scalp stays dry. Sticks work well along your hairline and ears without dripping. For bald spots, a wide-brim hat is best, but for parts and hairlines, powder or stick is the answer.