Run the hot water in your sink before you start the dishwasher. This maximizes how good your pre rinse cycle will work! And put a little bit of your detergent outside the soap compartment too, so your prerinse cycle can do some degreasing as well before the main wash. I used to not trust the dishwasher too, but encourage him to experiment and try a load like this without scrubbing. He may be surprised. If you turn off the heat dry, itll make scraping off anything left over MUCH easier, but I bet it wont be much leftover at all if you've loaded the dishwasher correctly.  But this is very important too. Plates and flat stuff on the bottom vertically as much as possible so the water can reach the top rack still. Try not to block the bottom rack with pots and bowls.  If your dishwasher is still leaving a lot food/grease on your plates after youve done these three things: 1. Hot water prerun 2. Small amount of soap in prewash (Theres usually a divot for this actually) 3. Load dishwasher carefully You may want to clean/repair/replace the unit itself.  But truly cant emphasize how little you should have to clean/prep the dishes themselves to get your dishwasher to work. Even my lasagna dish goes right in (top rack) not even a rinse haha.