White glue can be an alternate to clear varnish. A varnish is applied mostly on pieces of furniture to make them shiny. In crafting, it can also be used to make small crafts and artworks shine.
When I don't have the money and time to buy this varnish, I use glue instead.
Just apply a thin coating of white glue onto your craft. Let it dry and brush again with glue and repeat process to achieve best results.