Ideas for using low voltage high capacitance electrolytic caps?

[Ysjoelfir]

Hi everyone!
While searching through some of my stockpile I noticed some 15 to 20 year old caps with anything from 25 volts 45.000µF up to 150.000µF - at 6 Volts DC.... I love to tinker around with old stuff and would like to reuse them for some more or less usefull stuff. But I can't think about anything... I already used some of them (20V 100.000µF) to build an spot welding machine, but I have no idea about what I can do with the others, especialy with the 6 Volt things.
I attached a pic with some examples of the spare caps. (by the way, don't we all love those golden Roederstein caps? <3 )
Any Ideas?

[SeanB]

Charge to 3V and put a musical card on it. Should run for a day or so. Or make a low power LEd flasher and use them to power it. LM3909 is not exacvtly low power, you can do a discrete oscillator that is lower power, or use some CMOS inverters.

[Ysjoelfir]

Hi sean and thanks for your ideas! I actualy used some of the (even higher capacitance) caps already to power my leds outside in combination with a solar panel andna lighting sensor.
Yesterday I thought about a low voltage high current psu to use the 6v caps, maybe using 2N3055 as power transistor? Anybody ever built such a thing?
The 25v caps can be used in a chip amp with 18v or something like that..