Using the Cutter
Step 1: Before cutting, fill a spray bottle with water or isopropyl alcohol and lightly moisten the cutter's surface. This makes for easy, frictionless pushing. The smooth linoleum or Formica top won't mar the surfaces of your soap, and it's easy to clean. You'll also need to secure the cutter so that it doesn't move while you're cutting soap. This can be as easy as having it abut the wall behind your kitchen counter top or clamping it to a table. When you slide both the top and the bottom blocks, the wire will move back and forth to create any size bar you desire. If the wire doesn't go all the way over to the wooden guide, flip the cutter over. The movable wooden block underneath the cutter probably needs to be rotated. As you push the block of soap through the cutter, try to push it in toward the guide board as well as forward. In other words, concentrate on pushing in a diagonal direction.
The block of soap can wobble if it's not pushed into the guide, resulting in wavy edges on your soap. Try using a small length of 1" X 2" wood to push the block of soap. It gives you more control, and it eliminates dent marks and fingerprints. Before cutting bars, "clean" the slab. Set the wire about 1/8" from the guide, and gently push the block through. Trim all four sides. Then gently scrape off the flaws on the top and bottom of the block. These trimmed scraps can be re-melted or used as is.
Step 2: Now the block is ready to be cut into bars. If you want a 2" X 3" x 1" bar of soap, first take a ruler and measure 2" over from the wooden guide. Jiggle the wire over to this spot, and tighten it if it's slack. Make sure the wire is straight up and down, not at an angle.
Step 3: Push the trimmed slab through until you're left with six strips 2" wide.
Step 4: Now measure 3" from the guide, and move the wire here. Run the strips through sideways, and Cut into 3" lengths. You now have blocks of soap measuring 2" X 3" X 2".
For 1" thick bars of soap, set the wire 1" from the guide, flip the bars on their sides, and push them through again.