If you're talking about pyramiding, hydration is very important. I soak mine a minimum of once a day. I've done this since I started raising tortoises and have never had an issue with pyramiding or any other problems for that matter.
If you're talking about general care of the shell...there really isn't anything you "need" to do. One option for a cleaner looking shell is to use vita shell. It keeps the shell moist and it gives it a shiny look. Be careful if you use this product and keep your tortoises outside because it will attract ants.
yeah i agree with neal but some people will say not to put vita shell on i personally dont think it cause any harm or prevents any UVS getting to the shell unless you put a lot of it on its pretty thick.