Just to inform you...
Any bottled juice on a shelf (not refrigerated) is dead (it is basically just a flavoring). It has been pasturized (heated), so anything beneficial for the Master-Cleanse has been killed.
The reason for juicing fresh lemons is the live enzymes...that is what will clean your cells.
If you find fresh-squeezed, refrigerated juice, make sure it was squeezed that day and use it up within a day.
If you don't stick to the basic recipe for the MC, you won't get good results...so why bother.
Your body deserves the best, so don't take shortcuts.