We study the combined and separate effects of three parts of finite
multi-test-tube cut and paste DNA computing. First, we reformulate the
ideas of Csuhaj-Varju, Kari, and Paun; Freund; and Priese, Rogojine and
Margenstern about multi-test-tube splicing DNA computing in terms of cutting
and pasting as in Pixton's work. Pixton shows that with finite cutting
and pasting only regular sets can be obtained from a finite set of initial
molecules. The others listed above show that using filtering between a
finite number of test-tubes, each with finite splicing, any recursively
enumerable set can be obtained from finite initial contents. We confirm
their result for cutting and pasting. Second, we show that when only finite
pasting and filtering between tubes with finite initial contents are allowed
then the result must be context free and that any context free language
can be so obtained. Finally, we consider several forms of filtering and
several ways of combining filtering with cutting, pasting or splicing and
show that all give equivalent results.