We made the mistake last year of not using a thick enough filter - instead using cheese cloth and we always had some black dust like material on the bottom of our syrup. After more reading over the winter, we learned that it is best to use a felt cone to do the final filter, after burning down. I went to our local hardware store, ready to purchase an official syrup felt filter and saw that they were $16.75. After speaking with the sales associcate further, she informed me that if I had wool felt at home it would work just as well. Well, I took out my canning jar funnel and put the felt in it and poured the syrup right in and, for the first time, nice beautiful clearn syrup! I just used my felt that is a 60/40 mix of wool and I think rayon. It was more pliable than the 100% wool and draped nicely in the funnel.
We do a preliminary filter from the collecting bucket to the burning bucket with cheese cloth to get out any pieces of bark, etc.