Do not define the data type to "upload"

[eluser]Unknown[/eluser]
I want to use the library (upload) to upload files
but I will not define the type of file:

$config['allowed_types'] = '';
If I put it and tells me that: The filetype you Are
Attempting to upload is not allowed.

//$config['allowed_types'] = '';
Now if I remove that line I said: You have not
specified Any file types allowed.

Any suggestions? I do not want to define the type
of data to upload.

Thanks!