You can use Rowenta Sole plate Cleaner. If you cannot find it locally, check online at retail sites like Amazon.
If you want to try a home made cleaner,
Avoid abrasive cleaning powders or scouring pads.
Begin with a cold iron that is unplugged from the electrical outlet. Use a mild dish washing soap or laundry detergent to create a sudsy solution. Use a nylon mesh pad, sponge, or a clean cloth dipped in the solution to completely wipe off the soleplate of the iron. Wipe the soleplate clean with a damp cloth or rag.
If the soleplate is the victim of a starchy build up or corrosion of some form, you will need to use something a little stronger. Use a clean cloth dipped in white vinegar to remove the build up. Wipe the soleplate clean with a cloth dampened in clean water.
If this does not work, then you will need to heat a solution of white vinegar and salt until the salt dissolves. Using a clean cloth sipped in the heated solution, wipe the iron's soleplate clean. Continue wiping until you have removed all of the build up or corrosion. Remember to wipe the iron completely clean with a cloth dampened in clean water.
Let me know if you have any other questions. Thanks.
Read more: http://www.doityourself.com/stry/cleaniron#ixzz1L4J0N8Yh