I am a juicer of 15 + years, & if you juice regularly, you will develop a routine where you will get pretty quick at it. My centrificals probably clean up in 5-10 min. The Champion juicer is a very quick clean as well.
My Norwalk takes longer because of the rinsing of the bags that is required, so all total that juicer probably takes a good 1/2 hr.+ to clean. It will go quicker if you clean it immediately, while everything is still wet.
You can also clean up those stains by soaking the parts in a diluted mix of either bleach/water or vinegar/water. I believe a mix of lemon juice/water will work as well.
I did this with my juicers & they come out looking like new after an hour or more of soaking, depending on the degree of staining.