Answer:
Iβm white; perfect for cutting & grinding. For most animals I am a useful tool.
Alone I am 24th with a friend I am 20. Another friend and I am unclean.
I always run but never walk often murmur but never talk have a bed but never sleep has a mouth but never eat.
I help engines spin and pants stay up.
I am enjoyed by some despised by others. Some take me for granted some treasure me like a gift. I last forever unless you break me first.
A word of five letters, Upside down is the same, A shark does this, But itβs not to blame. What is the word?