I have cleaned both my X sensors a couple of times. The tools I use are all Visible Dust products. Don't know if anyone else is experiencing this, but the X sensors seem to get filthy in a hurry. I also see a lot more silicone spots on the sensor, probably due to the speed at which the mirror slaps around at max frame rate. Over the past 10 years I have had every pro body Canon has mad, in multiples, and none of them have gotten as dirty as my X bodies.
I'm about to launch into a couple of hours of cleaning because at f/11 and above the images are so cluttered with crud, they're worthless.