You don't want to only inhibit or temporarily denature RNAses, if you work with RNA you have to permanently inactivate the RNAses. I work with RNA, and I haven't seen anyone use ethanol to remove RNAses, I would not trust it to work reliably. RNAses are really stable enzymes, they even survive autoclaving to some part, so I would not be suprised if they can refold after ethanol exposure.
The usual methods to remove RNAses are
- Treatment with 0.1% DEPC (heat up to at least 60 °C, or autoclave if possible to remove residual DEPC later). Cannot be used with e.g. Tris buffer or anything else that reacts with it. DEPC is carcinogenic, so you should follow the proper safety procedures.
- Anything made of metal or glass, heat up to 250 °C for around 2 hours
- 1M NaOH for at least 30 minutes (you need to wash thoroughly to remove the NaOH)
You should be aware that anything that destroys RNAses will likely do the same to your RNA.
Autoclaving does not protect completely against RNAses, but it still reduces RNAse activity significantly. So while you should not rely on autoclaving to get rid of RNAses, in my experience it is sufficient if you start from a source that is unlikely to contain a lot of RNAses. Pipette tips (not loose tips out of a bag, to minimize handling) and millipore-filtered water are pretty safe after they are autoclaved.
There are also commercial RNAse inhibitors, but I've only used them in cases where I had to mix RNA and protein, and the protein wasn't completely RNAse-free.