My mother-in-law bought me a great mop, but I am told to put it in the washing machine after every few uses without any detergent. I use vinegar (quite a bit 1:2 ratio with water in a new empty spray bottle. However it is very important that you spray as you go, DO NOT use too much liquid. I cannot stress this enough, I find that is the cause of the streaking. If you aren't getting the floor cleaning only spray the unclean section repeated and try not to leave too wet.
If you get too much on then you will have to let it partially dry and then without anymore liquid or spray remop over it. Or perhaps its is or is on the mop that is the problem(an original agent on the mop when you received it or from past use?) The mop head I have is a 2 foot by half foot strip of with Velcro on one side and it is made of micro fiber that is 75%polyester 25%polyamide. Sorry I don't have a brand name. ... View related article.