I worked on cleaning the block tonight. I started some blockoff plates the other night, I finished the other two tonight (waterpump and crank position sensor holes). The orange stuff is an adhesive-backed silicone foam that I used for a custom gasket a while back.
LA's Totally Awesome is totally awesome. It's $1, made in USA, and works really well.
I used two layers of tape to cover the head gasket surface. The first layer is 3M yellow painters tape, the second layer is aluminum HVAC tape. The aluminum tape will give a little more protection from solvents and wire wheels. Thanks Jason for the recommendation!
All foamed up with some Awesome.
After 2 rounds of Awesome treatment, then wiped with wax and grease remover, then a little bit of wire wheeling: