Another method that I often use to get rid of pin-holes and fill seams in Garage-kits(aka Resin figure Kits).
Get a Tube Putty like Tamiya, Gunze(I use their pre-thinned putty), Milliput dilute it with thinner into a paste, apply the past and wipe excess off, leave to harden and tidy up.
Another option would be a putty that uses a kicker/hardener that is mixed in with it, not sure what the equivalent is overseas over here we got Tamiya, Mori Mori, Sube Sube,etc.
Hope this helps, not really that different from fixing flaws on a plastic models.