When I juice carrots, beet root, or other highly...

Yes, it is. When you have completed juicing, there is accumulation of pulp that you would discard. Turn the juicer back on and run some of this discardable pulp back through the unit, alternating with white, table sugar, until you have used about 1 cup of sugar. This polishes the twin gears and removes the stains. Then, turn the unit off and proceed with cleaning as usual.
There are also a number of things to keep in mind here
A. Do not use chlorine bleach on the twin gears. The ends of the gears are nylon. Chlorine attacks nylon.
B. Vegetable stains are on the inside of the machine where no one sees them
C. Vegetable stains are safe - chemical residues are not.