I nearly always use the Lime blinds from Ikea for planking cut to suitable widths on the band saw, I use an Ink pad on the edges to simulate caulking. If planking a deck I start In the centre and work outwards, when finished the whole lot Is sanded and coated with what ever you decide. Like David I also use cyno
May be I am too late. But I use coffee stirring sticks The best are from Costa longer and more consistent In thickness than most. The Important thing Is cost zero. Marker pen on the edges stuck down with PVA. Of course It depends on the scale of the model.
Yes coffee stirrers which are free and when fixed and sanded look great. Macdonalds for small scale. I must admit I often feel a bit of an idiot when nicking an handful of stirrers when I have only bought one coffee he ho.
I get all my family to grab for me, usually get about 200 a month from them. (£7-99 for a 1,000 on eBay). But free is best, I usually put mine in plastic containers to soak in stain then allow to dry on sheet of newspaper before using.