To muck out I first fork out the sodden straw, chuck all the dry stuff to the back, rake all the bits out of the cobbles, then brush it out with a yard brush. This takes almost 30 mins every day before I've sorted new bedding, water, hay etc!
I use good quality straw as it's free as I live on a farm. I've used wood chip before and it was a nightmare as it gets stuck in the cracks and holds the moisture!
I cannot perminently change the cobbles as it is not my stable and there is no other stable available. I'm also on a low budget!