Just use a couple of the white pellets in the water and don't use aluminium utensils on the raw caustic soda. Make sure the pellets are well dissolved before placing the liquid in the cleaner.
The description of the product states that it is mildly alkaline and mildly etches aluminium. Based on this, I would use 1 litre of warm water and add in a couple of pellets of sodium hydroxide. Give it a good stir until the pellets completely dissolve and then run your cleaner.
Following this, a good bath in isopropanol to get rid of all the water should see it much cleaner.
