Fastest way to get rid of chunks in file.

[invitro]

if a file had these in it
1.AAA
2.BBB
3.CCC

and i wanted to get rid of the CCC but keep the 3. what would be the fastest way?
I always make slow code for this using arrays

[b]Dim Index(5000) as string
Dim indexControl as integer
indexcontrol = 0

then i read the chunk input #1, a$
and then do a
for i = 1 to len(a$)

if the code finds the chunk it rewrites it by loading it into the array and killing the file.


Is there a better way? I was thinking of binary replacing the string with chr32.

?