Most companies are becoming alive to the fact that nearly all of their office paperwork is confidential, and as such cannot be disposed with without ensuring that is is being done so in a secure fashion.
If you are planning a one off clear out then the first thing to look at is how are the to be documents to be shredded currently stored. If they are already in boxes and you are happy for the whole box to go then no more work needs to be done other than ensure the boxes are in an accessible place for collection. However, if the papers are in sleeves in filing cabinets then you will ideally need to transfer them into shredding bags.
You can send your records in plastic wallets, in ring binders and without having to remove paper clips. None of these present a problem to Simply Shredding.
Should you be looking at a more regular collection service then contact your nearest branch to see which service will be most suited to your requirements.