I started these bibs two and a half years ago, when my oldest was just starting solid foods. I'll just sum it up by saying they sat in the closet for a long time. I finished them up a few weeks ago. These are the kind of bibs we had for my sister growing up. They work for little babies clear on up through toddlers. And the cover everything, not just the shirt collar.
I simply took kitchen and bath towels. Cut a circle in around where the neck should go (I used a bowl to cut an even circle). Lined it all with bias tape, made button holes, and sewed on buttons.
I made a lot...but it did take me nearly 3 years.
My cute models.