Had the same in my mirrors. I drilled a slightly bigger hole and flushed it good with some clean water. Worked great!

 

what do u use for removing the mineral build up???

 

Claybar or a secret of the trade for any hard water spots is vinegar

 

I did not see this stated before, so a heads up to 2011 owners. Don't bother drilling! I was going to drill my mirrors, but I decided to take one off since I have the heated mirrors and I wanted to take a look before I drill into any wires. I found that my mirrors already from the factory have a quarter inch section of the seal cut out the bottom and a v cut in with a spout that feeds it. I do get the drain marks and a white reside but it doesn't drain for days as others have reported.

 

Sprayed the mirrors on my 2011 and water slowly ran out of the bottom at the notch cut it the gasket at the factory. Drilled them anyways and they empty much quicker now.

 

Hmm maybe I will deepen the v notch a little bit. And see how that works.

 

Just an update on the 2011. I took off the mirrors again for a closer look at what the factory did, while there is a cut out in the seal and a V notch in the bottom, I made it a bit deeper with my trusty files. I filed the bottom and inside the mirrors. This is all but completely invisible to anyone not looking for it. When testing I found the stream is much steadier now.

 

Its good to have a steady stream!

 

When I took my mirrors off, I was shocked at what was behind that gasket - sand, bugs, dirt, and I'm guessing a lot of road salt. I took some pics of what it looked like but they didn't come out. Here is how I cut my gasket and where I drilled the extra whole. I now have a nice stream coming out of the new hole and out of the original weep hole.

 

Problem solved if you're not in the desert (i.e.: No more secret Jeep survival tactic). JK... This looks like a helpful mod!