Verified answer

normally a human body decompose in 3 to 5 weeks.

If you mean human bodies, they never decompose entirely naturally. There will always be bones remaining, and if you don't want any proof, then that option won't be the best one. Skeleton remains have been found from humans as well as other animals from prehistory, so imagine. That would be like millions of years ago.

There was a serial killer, John George Haigh, who used sulfuric acid to dissolve the bodies in it. I have heard (although I can't say for sure) that battery acid could be used for that. Search on the net for further information about it just to make sure. Sulfuric acid leaves no physical evidence of the body. But getting a large amount of it to dissolve a body can be difficult, and then you'll need somewhere to carry out the process, including an acid-resistant container to do it.

Cremation would be a faster option. But you would need a very powerful furnace to do this (which won't come cheap). And from the ashes there could be some bone pieces remaining, which could lead to DNA tests (so it's not foolproof if you don't want any evidence).

You could also try those meat grinders like they do on mafia movies. Don't know how reliable that method is, but if it can break down bones, you could feel that to an animal and get disposed of the evidence quite well.

Ask Beethoven. He decomposed after he died.

Does any one know why you want to knw this?

:-@

screaming