Fantastic! My husband came across these Enviro several years ago. Our opinion is they are an incredible addition to our lifestyle. We like to heat with wood but as we all know traditional split wood can be very messy and time consuming. With the enviro bricks, my whole family can participate in loading up the car and then stacking them in the garage when we get home. We got two palettes unloaded and stacked in less than 20 minutes. Any of the children can go out to the garage to get blocks as needed for the wood stove. While there is some “dirt” that is associated with its any product you would burn, the mess with enviro bricks is just a little saw dust, which is very clean and a small dust pan quickly cleans up.