I make logs for 3 months, it works well although some logs do not always remain whole after drying (in this case I wrap them in paper). I did a test, it burns long enough: almost an hour to a log. My entourage is a little skeptical about this type of log, the question is about the toxicity (I do my logs with all the cartons and therefore there are over inks). I do not know ...
In any case it fills my instinct recycler. THE return of each race, I told me "a packaging trash that leaves half live in the garbage" but "a quarter of a log cardboard more!