I designed a circuit that is similar to the circuit on the picture below. The main difference in my design is that I am using a 3V battery and more LEDs.
I am using UNPOLARISED capacitors because I am aware of the oscillating voltages on the two capacitors. I also manufactured the PCB and it works like a charm.
Because unpolarised capacitors are large, expensive and I found only THT (I want SMD), I am interested in using ELECTROLYTIC POLARISED capacitors - and assuming that it is not dangerous since it is a low voltage circuit (3V battery is used, so the reverse voltage on the cap should be max around 1V).
I have already tried the circuit with polarised electrolytic capacitors (specifications 330uF, 16V) and it works just fine, and the capacitors are cold, so it seems safe. But I would like a comment from more experience guys before I make 20 PCBs and than realize that after 5 days the capacitors cause a fire or something...