From left to right: treated and untreated dowel poles, thin and thick coffee stirrers and finally Scale 7 group walnut sleepers.
In many respects the dowel poles was the least successful as they still have a decidedly yellow tinge but I think further painting and weathering will tone this down. The coffee stirrers have a really pleasing grey hue which I am sure I will take advantage of sometime - it actually makes me wish I had done all my sleepers like this rather than my usual potion of Jacobean dark oak stain. The most surprising effect was on the walnut sleepers which have become almost as black as ebony.
They all smell slightly of vinegar and must be still acidic, so I'm wondering whether I should try and neutralise this using Bicarbonate of Soda (another kitchen find) or whether this may ruin the effect. Perhaps another test is due.