After glazing, what could I use in place of steel wool that leaves color in the nooks and crannies?

Blue shop towels are great for removing the glaze as it is drying. If it has dried too much you can dampen it a bit. The steel wool, when used, can add a nice textural quality to the remaining glaze, which is why it is nice to use. You can use a very fine sandpaper at times to remove glaze, or a Scotchbrite scouring pad. The throwaway board is a great place to try out different techniques for applying and removing glazes, so that you can see the various ways you can use these applications. It does help to test it out before applying it to your painting.