Answer from Radleys FAQ : Findenser is resistant to the majority of solvents and splash resistant to dilute acids and alkalis at room temperature. Extended exposure to acids or alkalis will attack the surface of the Findenser. It is important to clean off any chemical spills immediately after they occur.
The inner body of Findenser and the cone/socket, i.e. the wetted parts that come into contact with the substance being evaporated during normal use, are borosilicate glass 3.3, which has very good chemical resistance. (We can supply a data sheet on this material.)
The metal finned jacket is anodised aluminium, and the plug and seal are acetal and HT silicone.
Please consider the chemical compatibility of your chemicals with these materials. You can consult chemical resistance tables online. (It is not feasible for our R&D Laboratory to test Findenser with every possible chemical, so we cannot provide data.) As well as wiping off any spills, ensure there is not a significant concentration of corrosive chemical vapours in the air around the Findenser (e.g. by using the Findenser within our guidelines, so the solvent is retained in the Findenser/flask).
There is an advised cleaning protocol detailed in the Findenser instructions.