Is it possible to re-use ABS or PLA filament material from printed parts?
If so, what is the techniques to reform it?
If you're more interested in the recycling and reuse aspect than the re-print aspect, you could melt all the scrap filament onto a cookie sheet or into a bar (like in a bread ban). You could then manually work the material, or use a CNC machine to carve out your next thing.
This Youtube video refers to HDPE, but the same concept will apply to other thermoplastics.
This Youtube video uses a cookie sheet and failed prints.