I buy those tips by the box when I find them. Yes they do split sometimes if the glue bottle tip was cut off too low and it's too wide. Don't ask how I know that. The other thing I have found is they are not all the same thickness or size even when you buy the whole box. I have A small bottle of acetone I soak them in when they goop up or I can just nip 1/4 inch off the front of the tip. There are many different types out there so buy some and see what you like best.