So my 40D had extras with it when i bought it. Came with 2X 4GB cards as well as dust in the pentaprism. I WAS going to live with it (i thought it was on the focus screen, and when i installed the EF-D, it was still there; like an alien ship in Independence Day) I found a local place would clean it for $50. I then found this gem Save $50. Yes, it was nerve racking. But now i have 1 little spec of dust, instead of 4 nasty, heavy ones! I know the tutorial was for a 5D, but it works for the 40/50D and the 5D/5D2.