posted by Nuke .
After a Melting point determination, why can't you re-use the solidified substance and capllary tube for subsequent determination?
In reality you probably could, however it is not good science as it has been considered to be contamined or already used and a new substance or solution should be obtained. I know this is wasteful but, that is just how it is.
I don't think it is all that wasteful. Those tiny capillary tubes are IMPOSSIBLE to clean. Even if they could be cleaned who would trust them? You're right. Get a new one.