Dear Grower,
Flushing is an "extreme" technique and it cause a lot of stress to the plant and it is not a good idea because put so much water in a pot when plant are at the endo of their lives it could cause watering problems. Plants needs less water at the end, so your soil will remain moist for several days and it could be create a good environment for molds...
So, if you didn't overfeeded these plants, you don't need to do a big flush but you need only to water plants with only water (and molasses if you want but stop with mineral fertilizers). You have to create deficiency when plant is ready to cut!