For the most effective decontamination, we've found using Three Way as the lube for our Claying Rubber is the best option. This is a very specialised rubber compound that we’ve found to be super fine and won’t ever micro scratch or marr even the softest paints.
Begin by spraying one section of the car at a time (like the roof) and allow the Three Way to being breaking down any iron embedded in the paint. If you get no reaction, you can still use Three Way as a lubricant for the Claying Rubber, or use a double cap solution of your chosen wash instead.
After a minute or so, spray a few extra sprays of Three Way into your Claying Rubber and with zero pressure, gently work the pad over the panel in north-south, east-west motions, rinsing out the pad in a bucket of fresh water regularly. Rinse the section thoroughly with water and continue until the car is done.
Once you have finished, tip about 100mL of Orange Agent into your Wash bucket with a cap full of your preferred wash and half fill with water. Re-wash the car to remove any residue from Three Way, rinse and dry.
Our full Three Way and Claying Rubber guide can be found here.