When you remove a brick block, you get 4 bricks for one block.
When you remove a clay block, you get 4 clay for one block.
When you remove a sandstone block, you get 1 sand for one block.
I checked 0.4.x and 0.3.1 and this is still a problem. Everything else you get back what you put in ... except for sandstone.
It would be nice to recycle materials but other than DMs this is the only way of losing blocks in the game. Will this be fixed in 0.4.x?