Substitute for Dishwasher detergent ?

Regular Dish soap but just a smidge because it will overflow with suds like you would see on cartoons

I haven't had a dishwasher for 25 years. But years ago, if I was out of dishwasher soap, I used a little squirt of regular dishwashing detergent, like Dawn or Palmolive, in the machine. (Don't use too much or it will foam up!) Another thing I used to do was put a little bleach into the machine. It really made coffee- and tea-stained cups & glasses sparkle.

I'm sure the technology is much improved since my day.

A small amount of shampoo. I have hand-washed dishes with baby shampoo when I'm out of detergent. Rinse them well.

You could use a VERY small amount of laundry soap, maybe a tablespoon.

you can use regular dish liquid (dawn, etc.) just make sure to only use a little... make sure not to fill the detergent container up because if you do you will end up mopping the floors....bubbles and all

You can use regular dish soap and use the sink. It doesn't take much to wash your dishes by hand.