The trouble with brand new solid colored tees is they don't always stay new-looking for long. I'm forever trying to find ways to keep them out of the rag pile. Here's my quick fix for one that fell victim to a cooking spatter:
First, I hung the shirt in the shower and spritzed it all over with a diluted bleach solution (a.k.a. shower cleaner). I wanted to soften up the background color and give it a faded tie-dye look. After rinsing and drying, I lined the inside of the shirt with plastic and painted the design on with bleach. I went for the quick and easy approach and just winged it with a brush, but I think a stencil would work well for a more precise design.
After washing and drying, the design will be lighter. I like the faux batik look - and it occurs to me it might be nice to paint on another color using fabric dye. Lucky for me I'm kind of a klutz...no doubt I'll have more chances to experiment with the technique!