I am the only baking-type person who didn't know this, BUT... on the off chance that there is someone out there who doesn't:
When you're finished feeding your sourdough, use COLD WATER ONLY to clean up whatever utensils you've used!
Though you'd think it would be better for cleaning, hot water inevitably turns the mixture of flour and water into wallpaper paste. And soap just makes the whole thing into a slippery soapy mess. No amount of soaking in warm or hot water can accomplish what a hard spray of cold water can in seconds.
So there you go. In case you didn't know!