My mother was a cake decorator and caterer and I remember those nasty plasticized cloth bags you used to put frosting in and decorate a cake. Trying to clean those things was horrible. You had to run hot water in them until the shortening or butter in the icing melted off. It was a greasy mess. Whoever came up with the disposable decorating bags needs to get a medal.
I use the 100 count box that opens up and dispenses one bag at a time kind of like a facial tissue box. The 12-inch bag is perfect for decorating a regular 8 or 9 inch round cake or a 9 by 13 inch sheet cake. The bags are very easy to hold. They are cone shaped and you put one of the decorating tips on the small end and spoon the frosting inside the large end. Just fold the bag to close it and squeeze to get the frosting to go through the tip and onto the cake.
The bags are heat resistant so you can use them in candy making. Just insert the liquid chocolate and squirt it into a mold.
Once you are done, there is no muss or fuss. Just remove the tip and wash it out and throw the bag away. No more scalded fingers trying to get those cloth bags clean.