You should always include any demands you have for the Seller, in writing, in the Purchase Contract under Special Stipulations, including the moving of all personal items and any clutter you want removed. Once the purchase agreement is signed by all parties, all clauses and stipulations become legally binding which means you will have legal recourse, should the Seller default on his/her obligations and the closing cannot take place until all special stipulations have been satisfied and all contingencies removed.
Sellers may attempt to justify leaving old paint cans, doors, or scrap lumber behind if they were left by the previous owners. Regardless of who was initially responsible for accumulating the clutter, if you do not want it, ask that it be removed. The best time to ensure that all clutter has been removed is during the Walk Through. This is the time the buyer and agent should note any problems and create a document to be presented at closing specifying any items, which survive the closing, thus continuing to be the sellerís legal responsibility to fulfill.