The original use I found for Milliput was setting glass eyes in carved heads and this is still one of my main uses for it.
Here's a Grouse head after most of the carving has been done. The eye sockets have been drilled out just slightly larger than the glass eyes to be used. This allows some adjustments to the positioning to be made to get both eyes level and in line from above.
A blob of Milliput is pushed well into the eye socket and a glass eye pushed in afterwards. The excess Milliput is squeezed out around the eye and this can be moulded over the rim of the eye to hold it more firmly in place and to make the eye slightly oval. I chose Superfine White Milliput for this because the eye rings of a grouse are naturally white and it helps with painting afterwards.
The head is now ready for painting using artist quality acrylics.