-
The trouble with using your own shit is that DNA could be easily recovered from it. No, much better to use dog shit, as they're currently immune from prosecution. Or a variation on the above theme. Where I come from we have a quaint tradition of throwing burning shit at cars. It's called 'Shite Alight', which must be shouted out, in the act.
It was a very deprived, yet happy upbringing.
or bring a poo along with you ready prepared
smear on door handle