I used to do what you do. Now I just process in the food processer the pesto, put into freezer bags and make it fresh each time I defrost a bag. I process the garlic first then the pine nuts, with the oil add the basil and the parm an process a bit more.
I think I need one of those wee little processors. Then I’d be more likely to make it up fresh. I hate cleaning out the big one.