Advice on cleaning heavy dirt with mitt
 

I use the car pro wool wash mitt, it is very soft but it doesnt do a good job on tough dirt, i find myself havibg to rub hard with a microfiber cloth. Any ideas on what i can do?

Maybe clay bar the extra dirty areas?

You should soak it first with suds by using a foam cannon before you tackle it with a regular mitts. Make sure to use a 2 bucket method.

Are you doing a proper 2-bucket wash?

Give it a good paint cleaning and wax job so that the dirt does not stick to the paint as easily.

Of course

I just did a full wash polish and wax last week. We will see if these specs still end up staying on the paint

Then during the foaming process, ANY DIRT stuck to the paint will easily be loosened up and come off WITHOUT doing any scrubbing UNLESS what you are scrubbing is something like tree sap. If that's the case, you haven't clayed your paint like you should have done to start with BEFORE washing it. You can stick a glass dish with baked on meatloaf in a sink with water and soap and it will loosen all of that baked on meatloaf. Your car's surface is NOT going to get remotely as hot as that glass dish in an oven so the foam gun should loosen up ALL the dirt on your paint's surface.

The only reason the dirt would be stubborn is if you don't wash your car but once a month and you allow dirt just to sit on it day after day in the blazing hot sun. At that point, you are your own worse enemy. Again, that is provided that you are not dealing with something that needed to be clayed in the first place. Sounds to me like you are NOT using a foam gun. I can easily see that being the problem here, which is why I question your proper 2-bucket wash process.