At the very least, this is not conducive to a pleasant yoga experience! Skin and product oils, sweat, and dirt can penetrate the surface of the mat and can expedite deterioration of it. These elements can also make it difficult to practice yoga on your mat because they may make you slide. Be aware of when to wash your mat.
You should wash your yoga mat completely every couple of months, and more often if you don’t practice regular maintenance or you perform yoga every day. This can not only extend the life of your mat, but will also keep it from smelling and transferring bacteria to you. The more soil you see on your mat, the more likely it needs to be thoroughly washed. If your yoga mat is peeling or pieces of it are adhering to your clothes, consider purchasing a new mat. Use a solution of warm water and a mild detergent such as dish soap. Submerge your yoga mat in a bathtub and allow it to soak for a few minutes. This will help dislodge dirt, oils and any odors.