One of the characteristic features of prions is their resistance to a number of normal decontaminating procedures. These pathogens are resistant to processes affecting nucleic acids, such as hydrolysis or shearing [9]. However, agents that digest, denature, or modify proteins do have activity against prions [7]. The PrP purified from the brains of scrapie-infected animals (PrPSc) can be inactivated by prolonged autoclaving (at 121ºC and 15 psi for 4.5 hours), or immersion in 1N NaOH (for 30 minutes, repeat three times), or immersion in concentrated (>3 M) solutions of guanidine thiocyanate [10]. However, certain cautions prevail; it appears that inadequate autoclaving can establish heat-resistant subpopulations that fail to diminish with a further cycle of autoclaving [11]. Stainless steel instruments also may retain infectivity even after treatment with 10 percent formaldehyde [12,13].

Newer decontamination techniques are being investigated. There has been some success in sterilization using a combination of sodium dodecyl sulfate (SDS), proteinase K, and pronase [14]. A radio-frequency gas-plasma treatment has been shown to effectively decontaminate surgical instruments [15]. Another group has tested a decontamination formula combining copper metal ions with hydrogen peroxide [16].

>"combining autoclaving (even at 121 degrees C) with a sodium hydroxide treatment is extremely effective." https://www.ncbi.nlm.nih.gov/pubmed/10658760

Usually there is some sodium hydroxide in standard sodium hypochlorite bleach solution as well though, perhaps that explains why they reported it is the most effective of the chlorine bleaches.