Take good care of crocheting needles. The hooks are very important, if those are rough, they will hurt the spinning, and then we think that it is a problem of quality of wool.
When the needles lose gray steel bath and are bright on the tips, they stain.
Don't weave with light-colored loop, leave it for dark loop where you do not notice.
It is advisable to buy good needle, globally recognized brands and care them much.