A method of delivering a substance from dispensing devices 18, 19 via an attachment 1, comprises at least one dispensing nozzle 3, a first input port 4 and a second input port 5, where each input port is configured to engage with a dispensing device containing a substance to be delivered, a first passage 11 linking the first input port 4 to the dispensing nozzle 3, a second passage 12 linking the second input port 5 to the dispensing nozzle 3, where the passages intersect prior to the dispensing nozzle 3 to form a common passageway 13, and where the attachment 1 includes an user actuated mechanism 7 positioned at the intersection of the passages and configured with a passageway 14 to allow the substances to be delivered via the first or second passage of the dispensing nozzle 3. The method includes the steps of connecting a first dispensing device 18 to the first input port 4, and operating the user actuated mechanism 7 so that its passageway 14 aligns with the first passage 11 and the common passageway 13 to link the first input port 4 to the dispensing nozzle 3 and then delivering the contents of the first dispensing device 18.
