Rails CSV file upload character encoding issues

I know there are a lot of threads about this already, but none of the solutions suggested do not seem to work for me for some reason...

I am using:

Ruby 1.9.2

Rails 2.3.8

My users author CSV files in MS Excel and then need to upload these files to the web application. My web application and the database backend uses UTF-8 and all special characters, such as the £ sign, get corrupted on upload.

I am reading in the file like this:

@file = params[:import_file][:uploaded_data]

Then get encoding of the file using:

 source_encoding = "UTF-8"
 if @file.external_encoding
   source_encoding = @file.external_encoding.name
 end

For my test file the source encoding value is ASCII-8BIT.

Then I try to do:

@file.each {|line|
   print "#{line.force_encoding(source_encoding).encode!("UTF-8") }\n"
}

in order to see if all texts are displaying ok. However this gives me error like this:

"\xA3" from ASCII-8BIT to UTF-8

If I am trying to read the CSV with:

dataArray = CSV.read(@file, encoding: source_encoding)

No errors this time, but all special characters go as ? characters.

Any pointers where I might be going wrong or is importing CSV file authored with MS Excel just a mission impossible?

Regards,

Olli