After washing your brushes, you need to dry them properly in order for them to maintain their shape. I sometimes find that a beautifully proportioned brush flares out and becomes a ‘fat peacock’s tail’ brush when I lie it down on its side. So after some experimenting and Googling, here’s my method to keeping brushes in shape:
1) When drying your brushes, dry them upside-down to allow the water to drain through the bristles. This prevents the water from loosening up the glue that holds all the bristles together. 2 ways to do this: a) balance your brushes against your mirror/wall/something solid or b) put them in a cup.
2) To keep them in shape, fold 2 unseparated squares of toilet paper into about half lengthwise. Roll your brush handle with the toilet paper and bring the toilet paper upwards towards your brush bristles. The toilet paper acts as a brush guard to keep your bristles in shape and absorb the water.
3) Secure the toilet paper with an elastic band at the metal holder. Do not secure the bristles as you’ll end up with funny-shaped bristles. Alternatively, the moisture from your brush will act as an adherent and thus, you may not need an elastic band to secure the tissue paper.
4) Keep it that way till you need to use it next.
Hope this helps : )