I didn’t use any brush, don’t have one either just a clean micro fiber cloth. I just came to know that I very rarely put my phone between there and it has this Horween black leather case which probably has left these smudges, should I try cleaning it again? I used 1:30 @ Multi X.
On a bright side, the treated areas with CC Leather Conditioner is doing pretty good job, no smudges — it’s been few weeks since application.