The £1.99 household product Cillit Bang is being used to help clean plutonium stains at the defunct Dounreay nuclear power plant in Caithness.
Dounreay Site Restoration Limited (DSRL) said it would help reduce the £2.6bn cost of dismantling the site.
The cleaner's use has also drawn interest from operators of other nuclear sites in the UK.
A different domestic product has already been applied in the cleaning of contaminated glass tubes.
Randall Bargelt, of the Nuclear Decommissioning Authority, which owns Dounreay, said such innovative thinking would save taxpayers, who are funding the cost of the dismantling project.