Restore colour on your ABS 3D printed models. I use a pen torch to bring back the original colour from white marks after removing raft and support structures. Watch this video how is done.
https://www.youtube.com/watch?v=0T2pX9SHomI
http://www.youtube.com/watch?v=u2To3kHSaKA
Or dab on acetone to smooth the break off areas
@Daniel_Joyce you didn’t watch the video did you. 
Method 3: Using my rework station since I can set the temperature and easily focus on specific areas
Pieter, your rework station sounds awesome. How did you do it?
It never occurred to me to use a small paintbrush with the acetone. I’ve been wasting my time trying to use q-tips. Thanks for the share!
Heat gun, 2009 tip
@danleow Since a rework station is used to solder/remove surface mounted components from a pcb, it has a pen which blows a thin stream of hot air. You can replace the nozzle to control the size of the stream and the station also allows you to adjust air and temperature. If you are careful, you can touch up any printed piece without causing it to warp. I’ve used it extensively on PLA and ABS. You can also use it to soften up difficult parts and unlike an open flame, it doesn’t leave any black marks
Thanks Pieter! never knew about that now I know, but I did thought about using a heat gun but it uses too much electricity and too bulky.
@danleow I’ve found heatguns to be useful too. My one 3d printer has a hard time getting its heated bed to anything over 100 degrees Celsius. When I need such high temperatures I’ve found that a heat gun works like a charm. Once the bed is at the correct temp, the printer does not have any problems maintaining the temp.