What do you think he did?
Lots of options.
If guilty,I think he would have hidden them ,maybe under floor boards at his cottage or somewhere else that no one would look,then wash them when it was safe to do so.
He couldn't leave them at WHF as it would be thoroughly searched,too dodgy,and he wouldn't have wasted time washing them at WHF either.
And as Roch said ,he couldn't hide them in the countryside for fear of dogs finding them,also,he knew he would be in the spotlight so very hard to get a chance to retrieve them.
No,he had to keep them near by and deal with them when he got the opportunity.