Resin is subject to break down in high UV environments. We use the most UV resistant resin that we can but prolonged exposure to high heat and direct UV can cause distortion and yellowing. You can prevent damage by keeping a cover on the knob when it is not in use. Most resins out there for clear casting have a max threshold of about 140 degrees Fahrenheit. You may think that 140F is high but that is the maximum it can take. A hot car can produce heat high enough to blow your car windows out so take care of your resin and it will take care of you! If you run into a situation where the resin has become soft from high heat exposure simply bring it inside and let it cool and harden again. You can also put it in the freezer or refrigerator to rapidly cool it.
Cleaning and Polishing
If your shift knob looks a little bit dirty or smudged try to clean the knob with a clean microfiber first before you use sprays or cleaners. You should never clean your shift knob with any type of chemical cleaner. Degreaser, Some interior cleaners, Alcohol, should NOT be used to clean resin shift knobs. Read the bottle of cleaner you are about to use and make sure it is safe on all surfaces. If you are not sure, DONT USE IT!
I have no affiliation or sponsors with Maguire's, but they have an excellent product that can keep your shift knob looking brand new if it starts to dull. Maguire's PLASTX headlight polish works very well and is easy to use. You can simply apply a small amount of polish to a microfiber or an applicator pad and with mild pressure, scrub the shift knob section by section until the desired shine comes back. Wipe with a clean microfiber cloth and reinstall.
Wear and Tear
Loose Shifters, Crooked Knob
If your shift knob becomes loose often and you continually turn the knob to tighten it, you will damage the threads or the shift knob. The reason the knob is backing off could be for many reasons. The solution to this problem is to install a Jam Nut under the shift knob. You can start by installing the Jam Nut on the threaded rod, then the shift knob. Turn the knob until it faces the way you want so if there is text and it appears upside down or sideways this is the fix. Simply position the knob in the correct orientation and then snug the Jam Nut to the bottom of the shift knob. This will keep the knob from becoming loose or appearing crooked.