I simply use a muslin bag. I get them from my local home brew supply store. I tie up the open end using butchers twine. I have a plate cooler so I have to keep the boil as clean and debris-free as possible. That said, I do not add more than 1 ounce per bag, I dangle the bag (like a tea bag) to keep it suspended and I have never noticed any issues. I have had as many as six muslin bags dangling in my kettle, but it works! I suppose my utilization does suffer a bit, but I live with it.