This 3-in-1 brush from KarlsKicks is great for cleaning different types of sneakers. The brush has three different sides. There’s a side for cleaning suede sneakers and one has a nubuck block (watch this video for instructions: https://goo.gl/h2s4F4). The third side (the white/gold side) is for cleaning dirty soles and flyknit/primeknit.
The brush won’t fray the fabric or the suede on the sneaker.