I must share something with you which is only known by a minority of people, only because they work directly with manufacturers of cosmetic tools.
As soon as I found this out, I just knew I had to share this with you because I couldn't find anything on the internet about it.
We have all these strict EU regulations about ingredients in cosmetics but (as far as I'm aware) no tests to ensure make up tools are safe. To be truly honest with you, the idea had never crossed my mind that brand new make up brushes and (the biggest shocker) a pencil sharpener could possibly contain bacteria which can cause skin/eye infections.
Now for the science part, factories in China use blades for pencil sharpeners which haven't been irradiated. Now, irradiation is a sterilisation process,which kills bacteria on the blades of a sharpener or the natural hairs of a brush. Irradiation is a very complex process (hence why not all factories manufacturing these products do it) but it is necessary to avoid infection.
The really scary thing is some that people who may suffer from eye infections or skin irritation will probably never link it to make up tools, instead blaming a mascara or a foundation.
Now for the solution, go for a German brand pencil sharpener, such as "KUM", most major cosmetic companies use this brand, so you can check with them. I will also be conducting my own research because nobody else has, so I'll compile a list of safe brands for you after my research.
Also, thoroughly wash any new brushes/tools with a brush cleaning/sanitizing product, this is good for new brushes anyway to remove any loose hairs (especially if they are natural hairs which have been sourced without causing animals any harm or distress).
I'll keep you updated with my research.
Keep your make up tools clean and keep away from cheap Chinese sharpeners.