Source hacked here:

var

I: Integer;

List: TStringList;

S1, S2: Integer;

begin

List := TStringList.Create;

List.LoadFromFile('whateve

for I := 0 to List.Count-1 do

begin

S1 := Pos('<mytag>', List[I]);

if S1 > 0 then

begin

S2 := Pos('</mytag>', List[I]);

if S2 > S1 then

List[I] := Copy(List[I], 1, S1-1) + Copy(List[I], S2 + 8, Length(List[I]));

// 8 = Length('</mytag>')

end;

end;

List.SaveToFile('whatevern

List.Free;

end;