I found a clea plastic box like this 
  
 It is good for organizzing small stuff. But there was some ooooold foam layer sticking on the cover and that foam disintegrated leaving a gummy residue with a bad smell. I left it to dry , but after a week the stikiness is still there. 
Temporarily I solved the problem by covering it with dust LOL. 
It seems to work but I am thinking to clean that gummy mess without harming the box itself. What kind of solvent or detergent can be used here ? 
Thanks.