I was told years ago to never get your mats wet- if you need to wash it- dry it completely right after--- so the fact some of you soak your mats in a bathtub is pretty surprising....what is the purpose of doing this? seems like it would cause it to dry out become brittle... I've never heard of any one doing that before- I have mats that are 15+ years old- which are still just fine- and my big mat that gets used constantly I have replaced once just because the lines were pretty worn away & I wanted a new one- the old one I cut up into different sizes & still use them- I've never saturated a mat- I have used a soft damp cloth a couple times...i'm just wondering- what does it do for the mat to soak it in a tub? and how long does it take to dry it out, make it useable again afterward?