Cleaning
 

Very dirty mattress, should it be cleaned, or is it easier to buy a new one?

My advice, if you do not feel sorry to buy a new mattress, it is better to spend the money on the best and most versatile cleaner not only mattress. Or at least read about matress cleaning and you will understand everything for sure. After all, the benefits are many. And even a new mattress can't be compared with a cleaned one. Explore it!