• Wrap instruments in aluminum foil or place them in an autoclavable pouch.
• Autoclave at 121°C for 20-30 minutes under 15 psi.
• Allow instruments to dry completely inside the autoclave to avoid condensation, which can introduce RNases.
• Rinse thoroughly with RNase-free water.
• Air-dry in a clean, RNase-free environment.
• Heat instruments at 160-180°C for 2-3 hours in a dry heat oven.
• This is effective against RNases but may damage delicate instruments.
• Right before use, wipe instruments with RNaseZap® or 70% ethanol.
• Allow to air-dry or flame-sterilize briefly if compatible.

If you want to avoid autoclaving as in Raja Saha's answer, you can follow this protocol, but this requires an ETO sterilizer machine:

1. Clean the instrument with Kim wipes using 70% ethanol.

2. Wrap the instrument in ETO permeable sheet and perform ETO sterilization.

3. Heat the instrument at 180 C (2-3 hrs) in hot air oven OR 250 C for 40-60 mins.

4. Wipe your gloves with ethanol, and before use wipe the instrument with RNaseZap or use 0.1N NaOH (you have to soak it for 5-10 mins) (if using NaOH rinse with RNase free water afterwards) (Ideally use fresh gloves and ensure to never touch the outside surface with barehand, use gloves upon gloves)

5. Air Dry in a sterile environment with minimal chances of RNase contamination ideally keep in laminar hood.

If you want to make RNase free water best economical way is to Autoclave Ultrapure MilliQ water, does not completely remove RNases but eliminates the contamination significantly.

The main source of RNase you encounter in your work is the endogenous RNases in tissues and cells. In general, guanidium-based cell lysis kits effectively protect RNAs here. However, RNAs become more vulnerable to degradation in subsequent processes. To reduce this, the binding, washing and elution solutions in the RNA isolation kit are delivered as RNase-free.

Let's talk about the sterilization of equipment:

RNases are generally resistant to heat (I still use an autoclave), but additional UV usage may be beneficial. Some say they also apply NaOH solution, but it can make the situation more difficult (cause some unwanted consequences).

But as I said, the general sterilization process may be sufficient since the main source of RNase is the cell itself.

Note: do not neglect general RNase contamination prevention methods (such as wearing gloves, working on ice, reducing unnecessary contact of sterile materials with air, completing the job quickly).