As salamu alaykum. Before friday prayer, the people in my local masjid hand around a vessel for donations. I never donate that way, since this reminds me of how churches did this before I became a Muslim. For me this is immitating the Kufar, am I correct in this? And how should I best advise them?

Ustadh AbdulAziz al-Haqqan

I would not say it is imitation, but I would advise against it.