Some retired teachers may have been told at HR that they are NOT eligible to substitute teach. That information was incorrect. All retirees are eligible to substitute teach. A short form to fill out is required to make sure all who substitute teach after retirement are aware that there are restrictions on earnings. Once that form is filled out, one can substitute within the parameters of the retirement law.
Also, retirees (and other substitute teachers) who maintain their active Mass teaching license get a 3% differential based on the per diem rate.