Just cut the lemons in half and juice them with juicer.
After about 3 days, most of your solid waste will be gone and it will be mostly butt pee. You need to be near a bathroom for the first 2 hours after the salt water flush.
I am also planning to do the Liver Flush after my Master-Cleanse (master cleanse) is over. I will do it about one week after my MC, that's after I have started again on solid foods.