Is it appropriate to assign Mechanical Turk-type tasks as extra credit? By the end of the term, I always end up with quite a number of D and F students who want to improve their grades. Meanwhile, I usually have lots of menial tasks on hand during the summer, e.g. data entry, translations, proofreading, photo tagging, etc.


None of these tasks is work I am assigned or paid to do.
All of the tasks relate to my courses in some way and the resulting efforts would benefit the next group of students who attend my courses in the subsequent terms.
My school has no official "dead week", but naturally these tasks would occupy time that presumably the students would otherwise use for final exam preparations.


Is there any ethical or professional reason deeming it inappropriate to assign such tasks as optional extra credit, allowing students to move their 50 to a 60 or 60 to a 70 after ~10-15 hours of repetitive work?
As I see it, the grade in the class is supposed to measure a student's mastery of the material. Letting students improve their grade via unrelated menial work is not consistent with this standard and seems dangerously close to letting the students wash your car for extra credit.