cleaning dielectric from a blown cap and identifying caps

[cgray1497]

how would you go about cleaning dielectric from a blown ceramic capacitor?

the dielectric is white.

also i'm having some trouble identifying the capacitance. they are blue ceramic hi voltage capacitors that say:

472M
250V ~ x1y1
400V~C

and
102M
250V ~ x1y1
400V~C

I read on a different post that the letter is sometimes used to indicate the tolerance? for instance
27J 3kV would be a 27pF with 5% tolerance

[stj]

1st line is capacitance,
1st 2 digits are numbers, 3rd is multiplyer.

472 = 47 + (2 x 0)
4700
4.7nf

2nd line is working voltage and safety rating - in this case "x1"
*always use the same safety type*
3rd line i would ignore, i think it's just peak rating.

[Wizard]

Actually, electrolyte.

Cheers, Wizard

[Radio Fox]

Originally Posted by cgray1497

...I read on a different post that the letter is sometimes used to indicate the tolerance? for instance
27J 3kV would be a 27pF with 5% tolerance

Usually:-
J=+/-5%
K=+/-10%
M=+/-20%

[Radio Fox]

Originally Posted by Wizard

Actually, electrolyte.

Cheers, Wizard

Ceramic capacitors don't contain electrolyte.

[kc8adu]

without a pic i will guess it was tacked with rtv.peel it off.