Before testing, you'll want to be sure the X-Cap and Purpl Pro glass surface are smudge free. You can gently wipe with a clean microfiber cloth or towel. Be sure not to touch the center of the glass piece on the X-Cap.
After you've tested a sample, the X-Cap is disposable. It can be thrown away or used to cover and store the sample. The lid or second piece to the X-Cap is not needed at all during the testing process, just the cap side with the glass center.
The X-Plate can be soaked in isopropyl alcohol to dissolve any sticky substances. If you wish you re-use the plastic X-Cap instead of disposing, you can soak that in alcohol as well. Be sure to clean both before testing a new sample.