Dealing with loose hanks of tying material such as Krystal Flash and Flashabou can be problematic. I greatly prefer leaving the material in its original package so I’m absolutely positive of its make, size and color. The package also protects the material and keeps it from tangling.
To access the material while it’s still in the package, a hole punch is really all you need. Work the material up from the bottom of the package and then use the punch to create a hole right where the hank is drawn together. Now reposition the hank beneath the hole. Then simply pull out and snip off however many strands of material you need.
Some materials are bound at the top of the package. For these, I usually punch holes on both sides of the hank for access. The hook of your whip finisher is oftentimes the best tool for pulling out the desired amount of material. You can then use your tying scissors to snip it free.