The traditional oil to use is castor oil, try just a couple of drops and let it absorb before stirring as described above using bone or plastic spatula. The reason not to use metal is if the paste is made with genuine cinnabar (sulphide of mercury) it will dissolve a little of the other metal in time, cheaper pastes, such as those that come in tins, are now made with synthetic pigment.
I have painted a New Year picture every year for the last six years chiefly to use as a greeting to friends. This year I have made the pig a wild one at sunrise. The wild boar is an important symbol in the ancient Celtic cultures as it is in Chinese culture. Coincidentally the wild pig is also associated with the old Celtic lunar New Year ‘Samhain’ which falls in autumn. (Nowadays people mostly celebrate it on the last night of October to first day of November as it survives as Halloween and we have forgotten how to work out our lunar calendar.)
In ink (five lacquer ink and pine ink), cinnabar ink, and colour on xuan paper. As well as using Chinese brushes I made much use of a Chinese style brush of soft pheasant feathers I had just made myself. The seals are ones cut by myself in petrified wood.