electrolytic capacitor not used in tuned filters

All the available Electrolytic capacitors tend to have a large capacitance value which is suitable only for low frequency operations.
Tuned circuits usually are used in the MHz and above range which need very low capacitance values.

-Karthik

Right reachrkata !

To add a few details:
1. Ceramic capacitors are used in non critical tuned circuits ie., broad bandwidths. They are notoriously temperature sensitive and vary all over the band. In fact, they are very good Temperature sensors LoL !
2. NP0, N750 etc., temp compensated Ceramics are used for Freq critical circuits.
3. Polyester, Polycarbonate and polypropylene capacitors have better tolerance and are more temperature stable.