well, their costs are based on weight = declared, the insurance value is based on lost value = declared. Pellets are not a fire hazard, neither is your furniture/books. I would not send solvents or lithium batteries - just who is being defrauded, you only recover what you lost as stated in case of loss? My stuff is not high value - if I had $1 million of furniture - would I try and save $$ this way?
This seems like a bad idea. It's potentially fraud, and if your stuff gets lost, stolen, or damaged, you could be out a lot of money.