decontaminate

from The American Heritage® Dictionary of the English Language, 5th Edition.

• transitive verb To eliminate contamination in.
• transitive verb To make safe by eliminating poisonous or otherwise harmful substances, such as noxious chemicals or radioactive material.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To remove contamination or contaminants from, by a cleansing process; -- usually used of radioactive, infectious, or toxic materials.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• verb To remove contamination from something, and thus render it safe.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb rid of contamination