So I submitted most of my apps already and I had this one teacher who was like my favorite teacher who was supposed to write a rec for me but he was out of town for the entire break and finally emailed me the finished letter on January 1st when I already submitted most of my apps. The letter was really good and I want to include it in all of my apps but I already submitted them 
and I had 3 other teachers do recs (I don’t think they’re that good) and submitted those 3 instead. Would most ivy leagues and top 20 schools allow me to send them this extra rec (and would it have to be mailed or can my teacher email it to them?) even though he is a teacher and not a professor or person I worked in a lab for?
I didn’t apply to top 20 schools, but I got into NYU and I sent 4 recs and their posted limit was three. I’d go ahead and send it. The worst thing that will happen is admissions will ignore it.
Bump. So I want to send this extra rec to 7 of my schools: Caltech, Columbia, Cornell, Duke, Harvard, Harvey Mudd, and Princeton.
A lot of these FAQs on the site are really vague. So are all of the policies for sending extra recs for every college pretty much the same? I just have the teacher mail the recommendation to their admissions office? What information needs to be on the letter? My app ID?
I’m really confused, like here on the Princeton FAQ: https://admission.princeton.edu/applyingforadmission/admission-faqs/letters-recommendation
It doesn’t say how to send the extra rec.