All of our products are designed as outdoor products that don't require any care of maintance to last for many years (if not centuries). The only exception to this is our fountains. Fountains should be drained and the pump removed in climates that experience freezing temperatures.
Our birdbaths are designed to be left outside in freezing temperatures. Because the walls of the basin are sloped the outward forces exerted by freezing water do not hurt the stone. For cleaning birdbaths we recommend using a stiff brush to loosen up any debris then flush the basin with clean water.
Over time, our stone products will develop a natural patina of moss, lichens and many other things as it weathers. This is natural and we encourage it because we believe this adds beauty and character to our products. If you don't like this you can wash most of this surface patina off a stone by using high pressure water from a pressure washer. We recommend you never use harsh chemicals, acids or bleach on stone.
We usually get one call a year from a customer in a panic because a leaf landed on their bench (or birdbath) and left a stained imprint of a leaf. We think this is natural, beautiful and should be enjoyed and appreciated. It doesn't mean your bench is defective or damaged for life. More than likely the stain will go away naturally after several rainstorms. If a leaf stain on your bench seat would ruin your day we recommend you regularly (as recommended by chemical manufacturer) apply a stone sealer to any polished stone surfaces. You can use the same stone sealer you would use on a granite countertop on any polished granite, polished jade or polished basalt.
In short, we recommend you leave your stone products in the hands of Mother Nature and enjoy the natural aging process. If you do have a problem or concern, you can search 'stone care products' on the internet for stone sealers, stone stain extractors and any other products you may want to use. These manufacturers can tell you what their products are designed to do and if they are safe to use on a particular type of stone or stone finish.