Warning! Do not attempt on a day when your patience is waining!
This is an excellent Practical Life activity to do with a preschooler but it does take a bit of prep and a boat load of patience! Before you even mention the activity make sure there are no irreplaceable glass bowls anywhere near the area in which you and the child will be working! (I learned this the hard way...it was in the dish drainer and a heavy plate tipped over right on top of it!)
Fill up one side of the sink with hot soapy water.
Fill up the other side with lukewarm, clean, clear water.
Pull up a tall stool and wrap yourself and the child in your favorite aprons.
In our house, I wash the dishes slowly since Josh needs a bit of reminding as to where to place the dishes in the drainer. Anyway, after I wash a dish, I place it in the clear water and he pulls it out and dumps the water (preferably into the sink!!!) and places the dish in the drainer.
Hints and Tips:
I often place a clean towel on the counter spread out next to Josh for him to place bigger or awkward dishes. It is just easier for him and I do not have to do too much juggling in the middle that way!
Start off with a small amount of dishes the first few times! Maybe just lunch dishes to get both of you used to sharing this job.
Have fun with this! Do not do it too often if it is stressful for you, the experience will mean more if it is kept positive!