Silcone Storage bags

These storage bags are nice & thick but I had a horrible time trying to get the plastic piece back on the close them up.  It wouldn't slide easily on all but one of them. I tried wetting them & even tried putting some olive oil on them & they still didn't slide well. I was able to get one of the larger bags to close properly but not the rest.  The material didn't have any smell & was easy to clean.  I just wish they were easier to close. I'm not sure if it was some kind of manufacturer defect or what but I wouldn't purchase these again.