I use inexpensive polypropylene plastic trays that are meant to organize papers and things, I think the brand is sterilite. Sold at office stores and target, etc. They have flat bottoms ( good for toning and for using small amounts of solutions ) and the corners are angled enough that they pour out without dripping. There is a small hole near the "latch end" that needs to be covered with a piece of tape to keep them from dripping ( if you get one and look at it, this will be obvious ). One thing I really like about them is that the plastic is hydrophobic, and after you pour the liquid out or wash them they are nearly dry. I use pyrex glass baking pans for things where you need to be fanatical about cleaning ( salt prints, calotypes ), they have rounded corners and you need to be careful and use a funnel when pouring liquid out....
