ActiveRecord::AssociationTypeMismatch

I have 2 models:

mop, has_and_belong_to_many :contacts contact, has_and_belong_to_many :mops

when I save my mop Ii have the users coming in a an array: ["9",10"]

I am doing this to asscociate each one to a mop:

@contacts.each do |contact|     @mop.contacts << contact end

Contact(#44950470) expected, got String(#20837400)

It is giving me the above error. Any ideas?

Never mind. I looked at Ryan Bates complex forms example for the 100th time and got it to work using his method. SWEET.