I use my wychwood exclusive at this point and I use a silicone tube as the "bowl". Now, I do use a glass tube as the stem, and a SS mouthpiece. Actually ive noticed that the mouthpiece does wonders for cooling a hit... Restriction plus heat sink of the ss thermal mass. Yum... Uhhhh oh yea! So I use a bowl for about 2 weeks. Rotating it,mid way... I notice the following. 1. Silicone has a,nasty habit of,being spongelike as heat is applied 2. The above eventually causes the outside to sweat sticky as it cools over and over. 3. Thus causing massive discoloration and odur. So how often do you swap em out?