These are cardboard boxes that has been painted for the "hantaran -Malay wedding" purposes. When you paint cardboard boxes you need to put a layer of sealer before painting the background paint. No sandpapering is required. Make sure you put an extra layer of varnish after painting.
As I was doing this, a 90-year old sikh man came to visit my shop and what he said to me really touches my heart ....."You have so much talent in you. May you have a long life and don't stop painting as long as you live."
