If you mean the files look something like this:

1
2
3
unwanted text
4
5
other stuff not numbers
6
7
8
[download]

then something like

while (<>) {
    chomp;
    next if /\D/;  #will need more accurate regex depending on actual 
+number format
    # process the lines that have only numbers
}
[download]

OTOH, if you mean something else, then you'll need to give an example (which would have been a GoodIdea to begin with).

Udated: per comments by kyle, added chomp and comment that "rejection" regex will depend on ITmajor's real requirements.