We have now uploaded a ruleset that includes the following rituals:
Skati's Mark (for traders)
Remove Mark (for traders)
Scrubbing ritual (for thieves)
You can find it HERE
Also here is a guide to the symbols of Skyldingheim - these are the symbols that are used by Skylding traders. There will also be other symbols in the game which are attached to goods which will be similar.
Traders, we will provide you with a stack of these at the game.
Thieves, please return any of these you remove to the GMs. These can be handed to a GM or popped into the Powers that Be box.