Woodsman's Bucket Trick
Alright, this is simply the best damn method I have ever used.
Flip the cubes over (as described previously), and poke a rod (pencil or similar, etc) through to the factory made hole. Now push the clones stem through the hole at the round end first, so that it ends up flush with the flat surface on the other side. Then place the cube'd clone on the bottom of a CLEAN!!! white 5 gal bucket with about an 1/8 inch of ph'd water containing a bit of H2O2. (ratio for 3% / 1 oz per gal, 29% / 1ml / gal ) The peroxide makes all the difference. Spray the clones with the same solution to prevent mold/mildew (this can be repeated throughout the process of rooting in areas where there is concerns of molds/mildews). For 6 - 8" about 10 - 15 clones work well. Finally place a #12 plastic run off tray (made for potted plants to set on, 20 cents or so each in most stores). in the top as a lid. The #12's fit snug and make a seal. This keeps things out, keeps moisture in, and allows light through. The white 5 gal buckets fit well on shelves and in rows. They house them securely, and have handles for easy transport. Its stupid simple, and works like a dream.
Change out the water each day or two. Burp the Buckets daily. To change the water easily, drill a hole in the bottom of the bucket. Then set it in another plastic tray of the same H2o2 solution. When you are ready to change the water, pick up the bucket and let the water drain out the hole. Empty the tray, refill it, and set the bucket back down on the tray and let it fill back up to the same level. Repeat as needed. In a week or so you will have bare white fuzzy roots bursting out everywhere like a porcupine, and many will emerge from above the cube directly out of the stem from the high humidity. Blowing into the bucket a few times couldn't hurt, and is part of my practice despite practicality .
Enjoy!