Crack it open and clean. Use q-tips with soap water to scrub everything and buy some compressed computer keyboard spray and blast away then oil and grease. Should be smooth
^^^^
That.
I like a can of brake clean, over soap & water. If you dropped it you probably got some fine river silt inside, that stuff will make em grind. I use a Daiwa reel lube pen w/ fine needle to relube my bearings & Shimano white grease or the red Hot sauce grease on the slower moving parts (gears & drag washers).
Do watch it when disassembling, the small parts & springs like to jump around as stated above. A small set of quality drivers is really nice to have.
c/22