If your printer is like mine, then you know that the closer an angle gets to 90 degrees, the worse job supports do. I’m printing some Minions and really hated how the underside of the arms came out, even with supports dialed up to 25% fill amount. But then I noticed my soldering iron not put away from another project and it made me go “Hmmmm…”
And it works! If the soldering iron (or woodburning thingy, if you have, maybe, I dunno) isn’t hot enough to actually burn the PLA, then it works very nicely to add more filament to spots needing repair. The heat from the newly-added filament just melts the existing print enough to merge it all together.
The next to last image shows the results of just smoothing the new plastic with the soldering iron. The last image shows additional filing with jeweler’s files (but emeryboard or even sandpaper will work). Not perfect, but certainly better! I could spend all day sanding and filling to get it perfect, but it’s a Minion arm, for pete’s sake. 