Clean your blender by blending soap and water
Instead of sticking your hand into what is essentially a cup with knives at the bottom, clean your blender the easy (and safe) way.
Just put some dish soap and warm water in it and turn it on; the soap and water will spin fast enough to get off any hard-to-clean messes. If it’s not totally clean when you’re done, pop it in the dishwasher to remove anything still stuck to it.