http://i4pd4zpyhrojnyx5l3d2siauy4almteocqow4bp2lqxyocrfy6prycad.onion/resources/read/strategies-for-countering-police-access-to-dna-data.html
At best, DNA traces can be removed by wiping down and bleaching extremely smooth surfaces, and only if there are no crevices or similar things. Tools, paper, textiles or other objects with rough surfaces, on the other hand, are practically impossible to clean in this way, of either human, animal, or plant DNA (even this can be relevant, for example, if genetically modified plant traces are found on pruning shears).