You can use the same freon , know the inlet and out let , and better feed the freon from discharge towards the in take (reverse order) , so that u can expel things out , instead of pushing them more deeper.
hope this helps
having said that , the practical work is not as simple as it looks in writings. Do it all on your own risk , as one must be well experienced in handling Freon and gases.
use proper gears and tools , freon is not user friendly and can give you frost bite or can even blind some one.
Nitrogen can be used as well , that is a bit safer.
regards