It can vary between brands but Lactose (anhydrous), Hydroxyethylcellulose, Cetostearyl Alcohol, Magnesium Stearate & Purified Talc are the usual excipients. Trying to separate might be a bit bit futile. Some will soak theirs in water or cola but if you can get your's into a powder or even close then you've most likely at least destroyed some of the time release. It's the poly ethylene oxide formulations that seem truly difficult but those don't go into a powder. This is all said with the assumption that you understand the safety issues of destroying the ER mechanism, as in, use caution.