Unstable twisted magnetic fields are believed to be behind various transient events, such as some flares (especially, smaller flares in isolated loops), CMEs and other eruptions. Unfortunately, the magnetic twist in the corona cannot be directly observed. We use combined MHD/test-particle models in order to investigate thermal and non-thermal emission from twisted coronal loops. The aim is to find specific effects that can be used for observational detection of twisted magnetic fields. I will talk about several features in thermal EUV/SXR, non-thermal HXR and in microwave polarisation that might be used as observational proxies of the magnetic twist. I will also briefly discuss the problem of self-consistency in modelling of thermal and non-thermal solar plasma.