Yes, they hold their shape. Mine has kept the pattern for years!
The blue block becomes like a rubber stamp. You would ink it just like any other stamp on an ink pad; and clean it off as you would a rubber stamp. I have a SU! scrubber, and as I remember it worked great. I'll try to get my blue block out and play with it.
"This is the day that the Lord has made, let us rejoice
and be glad in it." Psalms 118:24