One of the heater hoses on my van blew and all the coolant came out. I've got new pipework now (thanks Spannerboy) and am going to be refilling the system this evening. But there's quite a lot of evidence of rust in the header tank - at least, it's got a tan coating on it

The question is, do I do anything about it? I take it any cleaning solution like soap/washing up liquid is a total no-no, due to the salt in there. But are there any sensible cleaning measures I should be taking, or do I just fill up the system with antifreeze and so on, expecting that to do the cleaning for me?
Thanks as always
Richard