Don't throw it away then...and if it never bubbled, but there is "gunk," it wasn't sealed well enough for the airlock to do its thing. That's not a very big concern - even a poorly sealed lid will keep out most of the contaminants that you're worried about. You should probably taste it. If it tastes ok, leave it alone for another week or two, then bottle. Invest in a hydrometer and learn how to use it - that'll help keep you out of trouble in the future.