Rubber, plastic, and other flexible nonporous surfaces do not respond well to paint. As a result, conventional techniques using using acrylic, lacquer, or other paints will typically not yield long-lasting results. Painting rubber surfaces, like boots, essentially coats it with another form of plastic, causing cracking and peeling over time. Therefore, the solution is to dye the boot with a specialized spray that seeps into the rubber, coloring it from the inside out.
Thoroughly clean the boots using the alcohol or degreaser. Remove any dirt or contamination that will interfere with the dye soaking in.
Apply a light spray of dye, following the dye maker's directions. Only spray a thin coating. You will see the original color through the first coat.
Spray each additional layer in the same manner as the first, waiting 30 minutes between coats. Resist the temptation to spray a thick coating; runs and drips will result.
Inspect the boots after at least 30 minutes after the last application. Apply short bursts of spray to cover any gaps.
It will take so many coats of light-colored dye to change dark colored rubber boots that it may be more economical to simply replace them. Dying from light to dark is recommended.