The mesh tops on my OBOZ allowed sand and dirt in and then trapped it. I noticed they felt heavy but they got to the point that they were so swelled up from trapped sand my toes were being smashed. I tried a shop vac and compressed air to get the trapped dirt out. Right before I cut them open to get the trapped sand out I returned them to Rei. Less than a year old and I buy a lot from them so I took the refund and bought a pair of Vasque. They have some mesh as well. Has anybody else had a problem with dirt getting thru the mesh and not coming out?