How can I safely remove putty plugging the dipstick hole?

[reflectionpoint]

For the most part, but caliber does not always equal decimal size. At least not precisely. For instance most .38's are closer to .35 (usually .355 - .358)

But yes, in this case a .25 caliber brush would probably work well.

I was just bein' a smart a$$--I went and measured my .25 brush before I sent that to make sure I wasn't being entirely innacurate or misleading.