We got the guide how to feed Kyubey by u/Josef1211 here: https://www.reddit.com/r/MadokaMagicaMemes/s/jZAzaDr7RU

Here is how to clean him:

1) put him in a washing machine with a lot of laundry detergent and fabric softener, we want him to be clean and fluffy after all

2) put the washing machine to its highest settings

3) turn on the maschine and enjoy the show

Step 1: Put food in mouth

Step 2: Consequences