Fillers
These are a few of the type of fillers I've used when post processing my 3D prints. The safest and easiest method I've found is the Elmers Woodfiller, but if you're looking for a more durable solution, Bondo is the way to go. I recommend checking your local hardware store before buy these on Amazon as you can usually get it cheaper.
Gorilla High Performance Wood Filler

Gorilla High Performance Wood Filler

Elmer's Probond Max Stainable Wood Filler

Elmer's Probond Max Stainable Wood Filler

Bondo Plastic Metal

Bondo Plastic Metal

Bondo Spot Putty

Bondo Spot Putty