Yes it needs to be flushed, and oiled as well. The best bet is to remove the line from the spool, and place the spool bearing side down, in a container of solvent, so that the bearing is just submerged. You could also hit the bearing with some CRC Carb Cleaner as well instead of soaking. But remove the line cause once any solvent gets on it, it's trash.
You could remove the pin, but I do not suggest that unless you have the correct tool to push the pin out of the shaft, and back in. Some use a pair of Channel Lock pliers, but it's too easy to slip and screw up the shaft.