I use a metal strainer.

I had to try out a couple of recipes in order to get one that works well.

My recipe:

Oat Milk:

1. 1 cup oats

2. 6 cups water (chilled)

3. 1 tsp vanilla

• Add all to blender and blend on high for 30-40 seconds
• Strain with strainer 2x
• Add maple syrup for flavoring (and/or honey) 3 tbsp

Keeps for about a week.

Theres some other similar ones like: https://www.loveandlemons.com/oat-milk/ that work out well and may keep for longer (salt).