it helps to clip them as you construct---as in when you finish a block-and press it- turn it over and (clean it up)
again as you put them together-
you do not have to worry about every single thread- but make sure there are no (nests) globs of threads anywhere-
or long pieces that will show through if light fabrics are involved.as for the starch- i don't know that it really makes alot of difference; if the fabric is going to fray it's going to fray- and i don't think pre-washing is the problem either- it's just all the handling-
it makes it easier to clip them as you go-then it's not such a daunting task at the end.