Use the grey paste on the canvas/hemp side of the strop. Working the paste in the palm of your hand and spreading over the area you are going to use to initially align your razor blade, before using a leather strop.
Use the clear paste (Yellow) on the smooth leather and work the paste in well to prevent the leather from drying out and cracking. Once the strop is well oiled, you are ready to strop to give the razor a keen edge before shaving. The leather must be without any nicks or cuts otherwise your razor will be ruined. It is advisable to own a hand strop as well as hanging strop to help perfect your technique.
Hang the leather hanging strop on a stable hook in the wall and pull it tight. First use the coarse side of the strop (canvas/hemp) and then the smooth side(leather). Apply the razor with the blade side flat onto the strop, using light strokes back and forth, up and down the strop until the blade is sharp enough to cut a falling hair in the air. Please see our How to use a Straight/Cut-Throat Razor to see a diagram on the stropping technique.
You use the same method with the hand strop, which is probably slightly easier to use as these strops are hand held on a flat surface.