I have family members that like to sprinkle lemon juice on broccoli and other things at the dinner table. I don't like the ugly green lemon juice container on the table. For years I recycled an empty soy sauce bottle, but the red lid just rubbed me the wrong way. I finally discovered a little decanter that works perfectly.
However, when it's emptied and time to refill it, the dishwasher doesn't get all of the lemon pulp off. The last time this happened the idea to use rice popped into my brain, so I tried it and it works. A bottle brush would probably do the job as well, but that would entail a trip to the store. It's nice to be able to avoid that.
If you look closely, you'll see the film on the bottle in the upper left corner. I put a tablespoon of rice in the bottle, filled it half-way with water, plugged the hole and shook it for a couple of minutes. Then I drained out the rice and water and it was sparkly clean again, ready to be refilled.
So, little tricks work for me. I hope this one works for you if you ever need it!