I like using a wine cork rather than a pencil when I'm making t-shirts. If you want to use a pencil eraser, that's fine. But, then you can't use that eraser after (which is, like, half the function of that pencil). So, I just don't feel like it's the most economical craft. Wine corks are basically trash anyway, so you're rescuing them from the garbage (before, well, throwing them into the garbage).