For awhile I had one of my 25uf caps in parallel with the capacitors in my BC-610D for a few months and it never showed any signs of heating. Cool as a cucumber as they say.
It was running at 2100 vdc on fone & 2600 vdc CW. It really helped the regulation but the bleeder was not sufficient and the bleed off time was too long causing me some kind of problem that at the moment, I can't remember?