Of course, in light of the other responses, I suspect that I've been misled by your use of "remove": you just want to skip the irrelevant lines.

Which actually raises the question of whether you're interested in the header lines:

New file :
CPN     Quantity        MPN     Vendor  

which lie between the first an second section (you may well be, since these will allow you to spot the fact that you are indeed changing section).

However, if you're only interested in the data lines

51-0597-000     15      06035C103MAT2A  AVX themselves 

then:

  while (<INFILE>) {
    next unless
      /^(\d{2}-\d{4}-\d{3})\s+(\d+)\s+(\S+)\s+(\S+)$/;
  # Not only have we thrown out the garbage,
  # but the data fields are now in $1..$4
    ...
    more processing
    ...
  }
[download]

will skip all the non-data lines, as well as breaking the string apart into its constituent fields (you can obviously taylor the regexp to your precise needs, if you need to break out the middle component of the first field, for example).