for (1 .. 10) { 
    require "./foo.pl"; 
    delete $INC{ './foo.pl' };
}
[download]

In this case, you simply shouldn't be using require. Use do instead:

for (1 .. 10) { 
    do "./foo.pl"; 
    die $@ if $@;
}
[download]

require is the same as do, except it does some things more, things you specifically don't want, except for the error checking.