I also have my students grade their own homework at home. I gave them a handout with instructions. 1. Complete the homework assignment. 2. Correct answers with a color pen/marker. Write how many they got wrong on the top right corner. 3. Put a question mark by the ones they missed or have questions on. 4. Ask questions at the beginning of the class when I go over with them. This seems to work very well in my class. I just give them full credit as long as they come prepared and ready to ask me questions after following instruction numbers 1-3. This also saves time for me. I don't have to collect and grade each homework. I give them warm up questions at the beginning of the class and walk around checking their homework. But I make sure they have done all the assignments and have self-corrected them.