Sludge should be EASY to remove! Oh so easy! A few flushes and...voila!
And...as an aside...Olive oil is 'good fat'. Your gallbladder needs good fat. (it's the hydrogenated oil that it doesn't need) Olive oil is cholesterol free. This 'good fat' activates the bile to be released...so it ensures that your liver and gallbladder don't stagnate. A completely 'no fat' diet isn't good for your liver and gallbladder because then the bile just sits there and stagnates and creates stones.
Olive oil, flax seed oil....these are good fats.
Check out Dusan's link below...
Let us know how your flushing goes...because I am sure that you won't have to get your gallbladder out! No way.