Abstract: A method for collectively sampling a plurality of cargo items for contaminants such as chemical residues. The items are placed in a generally airtight chamber and agitated physically to release particulates and vapors from the surfaces and interior of the items. The methods of physical agitation include vibrating the items, and pressurizing and depressurizing the chamber, with the pressurizing being done by introducing bursts of high pressure air into the chamber and by directing jets of high pressure air at the cargo. Optionally, the high pressure air may be heated or mixed with solvent vapors. This physical agitation drives particulates and vapors of contaminants into suspension in the air in the chamber. Air withdrawn during depressurization is passed through a collection system to collect the particulates and vapors for subsequent analysis.