I am researching this subject in some detail, as I need to repair/replace my radiator very soon due to a break in the plastic upper tank.
I personlly feel that the use of the proper antifreeze is the main thing needed to keep these radiators flowing properly for many years to come. You need to prevent, rather than try to undo the damage, becuase it's really much worse than just the restriction that IS caused by the use of the wrong antifreeze and/or poor maintenance. For detailed analysis of this topic, let me save you some time, and suggest this link to topic thread # 13292:
special coolant for MB?
What I have found is that once one of these radiators develop a problem, especially with the plastic tank(s), it is almost impossible to get it fixed right, and it ends up being less expensive to just replace it.
Depending upon your level of sensitivity to "genuine" Mercedes parts versus aftermarket, that means either a genuine Behr radiator, a Behr aftermarket radiator made by them, but without their name on it, or a high quality aftermarket exact copy of the original from Nissens in Denmark. There are many other aftermarket radiators available, but I don't have confidence in a product when the company selling me the item asks questions like: "is that with an automatic or manual transmission?; does your car have a turbo?"; and the ever popular, "that's for a diesel, isn't it?".