People, Bruce Hood reports, are generally reluctant to put on the cardigan of someone else, even knowing it has been cleaned, once they've been told that this someone else was a mass murderer (like Jeffrey Dahmer or Fred West). He then considers possible explanations as to why they should be thus reluctant. His suggestion is that a 'sense of moral contamination' is at work - which sounds plausible. Hood, however, rejects the idea that this could be due to simple association, preferring the hypothesis that we think 'there are invisible essences to things that make them what they are'. This I find a lot less plausible as an explanation for the reluctance. There may be some who do indeed think in terms of invisible essences, but I don't see how the assumption that they do adds anything to idea of contamination through physical contact. I don't need to believe - and in fact I don't believe - that a cardigan shares some essence with its murderous owner to be put off the idea of putting on his garment. To that extent, simple association does seem to do the trick, even if one can't justify this rationally; and even if, as Hood notes, not every kind of association works in the same way (since, for example, reading a book about the killer needn't produce the same sense of contamination).
Think of the opposite phenomenon, which Hood also mentions: people wanting things that have come into contact with others whom they admire - signed copies of the books of favourite authors and such. In order to want the signature, do you have to believe that having it in the book will give you something of an essence that also inheres in the writer? This doesn't strike me as a serious hypothesis. Even non-essentialists attend book signings. People like mementoes and keepsakes; they visit places where famous people have lived or where certain historic events took place; they look at monuments and statues, artefacts that were owned by the now dead. I don't think such behaviour depends, or at any rate need depend, on a belief in invisible essences.
