original: They can also be used as a general test tube substitute particularly when a larger volume is desired.
simplifications: They can also be used as a test tube if a larger size is needed. They can be used as a test tube substitute when a larger volume is desired. They can also be used as a test tube substitute. This is especially true when a larger volume is needed. They can be used as a general test tube substitute especially when a larger volume is needed. They can also be used as a test tube substitute. They can also be used a test tube substitute, when a larger volume is desired. They can also be used as a general test tube substitute particularly when a larger volume is needed. They are also a good fill-in for test tubes when something is needed to hold more size. They can be used as a general test tube substitute.  Particularly, when a larger volume is desired. They can also be used as a general test tube replacement, particularly when a larger volume is desired.