First to get the paper saturated simply put it in your palette on top of the sponge, place in the sink and run hot water over it. Let this soak over night use lots of water! This is very crucial for getting the paper wet enough.
Then sit the palette on end and let most of the water drain. Now you are ready to paint!
I put several layers of paper in at once. It really works! When I am ready to paint I always have a wet palette.
Now for the cleaning. It can get a bit musty smelling, however to combat that I always clean my sponges out with some hot soapy water. I do this about once a month. I let them dry and then they are ready to go again.
I also have found that if I put a light spray of Clorox "Clean Up" under the sponge when I add the paper it keeps moldy smells from building up.
I will replace my sponges about 2 times a year. They just don't seem to last any longer but that is really a good amount of time don't you think?
For oils I use Artists Palette Seal, this keeps my oils moist and ready to use,
For travel I have found that the Painters Pal is the best! It is small and compact and can be taken on a plane.
They are really all great paint savers and very reasonably priced!
The best place I have found to buy them is from Jerry's Art Arama
I am not in any way connected with this product or company.