I always relish an opportunity to use up ingredients that are past their best. The thing to do is make breadcrumbs with stale bread whenever it's to hand. Stash the breadcrumbs in airtight bags in the deep freeze and use whenever needed, without thawing first. I am not totally old-school, though: I don't grate my stale bread to make breadcrumbs, but blitz it in the food processor. As a final note on the breadcrumbs, may I suggest you measure in volume not weight? Every batch of breadcrumbs seems to differ in density so much that when I cook with them I go by cup measures, but I have given the weight as well for those who feel reassured by that. How much or little you use here doesn't matter enormously, though. It's just not that kind of recipe. For US cup measures, use the toggle at the top of the ingredients list.