Raise your printers bed temperate to 60° via the LCD or through the Cura LE software.
Spray the PEI surface with the 50/50 mix of water/isopropyl alcohol and let sit for 30 seconds.
The water here helps activate the PEI surface!
This also allows any oils/dust/debris/glue stick that may be on the bed to break down and dissolve into the water/alcohol mix.
Use the abrasive pad to scuff the surface of the PEI. This will open the PEI up and remove stuck on residue.
Start with a diagonal pattern across the entire bed surface.
Rewet the bed with water/isopropyl alcohol mix.
Scuff the PEI surface with a second diagonal pattern at a 90° angle from the first
Be mindful of the water/isopropyl alcohol mix.
Always keep the bed wet, but not saturated.
If the surface dries before final cleaning, it can leave a powder residue on the bed surface that will prevent print adhesion.
Spray more of the water mixture onto the build surface.
Wipe surface down with a cleaning cloth to remove the residue left by the cleaning/scuffing process.
You may need to spray and wipe down the PEI surface multiple times to ensure all residue is removed.
If you notice any water under the glass surface, remove the glass/PEI print surface (after it is cooled) and dry with a clean cloth.
Once you have removed all of the water/alcohol mix and ensure no more residue is on the build surface, turn the bed temperature off.
Your build surface should now be lightly clouded with a crosshatch pattern and ready for prints to adhere with that perfect stick!
You can also perform this on the smooth magnetic flex bed.