I am trying to make a t shirt logo but want to alter my image so it looks a little faded and worn. I have tried using the a small eraser tool to remove fragments of the design but that just results in the 'canvas' beneath showing through, in my case white, where as I would like the removed sections so be completely see through, allowing the t shirt fabric to show through when printed. Can any one suggest a solution?

You could turn the visiblity of the background layer off so that only your painted design was showing.
If you do need a background block colour (e.g the standard white background layer), you could complete your design then merge it with the block colour layer below and then do some 'distressing' work with an eraser to get the final effect.

Thanks for the reply and tips.

Actually I am slowly figuring this out. I am now using the Global Selection Mask and I am trying to delete the mask i have created from the image I have. I have managed to a certain extent but I have noticed any white in my image is uneffected by the mask(??)

After much messing around I have figured it out and as usual it was dead simple. I simply had to draw over the Global Mask, then select my orignal image and then 'DELETE'. and that was it!