I would use potassium permanganate solution. I make mine up from crystals with the resultant solution resembling a rose wine. Take care not to get this on your skin or clothing as it will stain. Immerse the items for 15 minutes and then rinse - tap water should be fine. Of course, this is very likely to kill off any nitrifying bacteria and/or any other bacteria on these items. But, your main tank should already be populated with bacteria assuming that it has its own filtration.