Can you tell me more about "re-enterable" potting compound?
I've used raytech magic gel which is one of the more commonly used re-enterable potting compounds. 

The mixed compound starts off with a consistency like that of a weak sugar syrup, 
after a while it sets into a fairly tough greasy (with silicone) jelly. you can bounce
things off it and it's fairly resistant to being torn.

To get it off you tear or cut through the gel to get the board or wires out, and then clean the remainder off. I used Iso-propanol and compressed air which did the trick fine.

The videos on their site show what the stuff is like to work with. I'd recommend it - at the cost of silicone all over my lab and hands, it's saved me having to rebuild things from scratch.

The other reason to use it is the chemicals are much better for aquatic life than the typical bis-phenol-a based potting compounds.