Every two years of so I've had to replace my CX-5 plastic dash lens because it gets speckled with yellow dots that won't come off. Any idea why this happens?

 

Looks like some form of cleaner chemical residue/overspray to me.
But then again, I have no idea what the environment is where your vehicle is used or what work you do.
Meaning I have no idea what substances the exterior/interior are exposed to.
Examples: We have a local cement plant which can permanently damage the interior/exterior of any vehicle parked there for more than a couple hours.
Local boat yards some fiberglass resins can cause this even if it's just on your work clothes and you get in the vehicle (especially gloves).
Some types of insects can do this, but you should have seen them by now.
You may be able to use some plastic cleaners on your old ones and buff out the spots which would save you some cash at the expense of a whole lot of time.

 

It appears that something has been sprayed in it with some regularity. It could be almost anything which is sprayed, like soda, vinyl or leather cleaner, windex, etc. What have you tried to clean it off? This is certainly not normal.

 

I tried plexi-clean, windex, car wax, baking soda/peroxide and rubbing compound without success. On the one I replaced two yrs ago I even tried acetone, but that scratched the surface. I don't use harsh chemicals on it when cleaning... usually 303 protectant, windex or an interior detailer like from Chemical Guys or Car guys.

I only have 2 thoughts: 1. This car is parked outside and somehow the Texas heat causes it, or 2. my son sprays some type of drink on it. It seems very odd that I'm on my third lens in 7 years.

KP

 

It would be better not to spray anything on the screen, but to use something like screen cleaner sprayed on a microfiber cloth to clean it.

 

There are hundreds of types of plastics and plastic formulas, and you need to match the correct cleaner with the plastic you are cleaning and that's not always easy to do.
Never spray cleaner directly on to plastic put it on a cleaning cloth.
It is wise to check the SDS (safety data sheet) of any cleaners or products you are personally exposed to.
Windex contains ethylene glycol chemicals that can harm plastic and/or spot it. Windex with ammonia is even worse.
Chemical Guys and Car Guys products do as well as other chemiclas that may cuase plastic damage.
303 Protectant does not list the chemicals used on their Safety Data Sheet simply says, "Trade Secret". 303 has that same milky looking substance you show on your cover.
I wouldn't use any product that does not list the chemical ingredients as you have no idea what it will do to you and what you put it on.

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Plastic cleaners or cleaners in general will not take that out. Even plastic polish in not likely to remove the damage. Whatever was used on the interior has something not designed for interiors of vehicles.
Because the plastic cover is removed you can now repolish it starting with 1000 wet and the ending in possibly 4000 and then apply plastic polish with a microfiber cloth and buff lightly and you should have a nice clean lens again.

 

kprzw Welcome to the forum