How do I enable/disable log levels in Android?

The Android Documentation says the following about Log Levels:

Verbose should never be compiled into an application except during development. Debug logs are compiled in but stripped at runtime. Error, warning and info logs are always kept.

So you may want to consider stripping the log Verbose logging statements out, possibly using ProGuard as suggested in another answer.

According to the documentation, you can configure logging on a development device using System Properties. The property to set is log.tag.<YourTag> and it should be set to one of the following values: VERBOSE, DEBUG, INFO, WARN, ERROR, ASSERT, or SUPPRESS. More information on this is available in the documentation for the isLoggable() method.

You can set properties temporarily using the setprop command. For example:

C:\android>adb shell setprop log.tag.MyAppTag WARN
C:\android>adb shell getprop log.tag.MyAppTag
WARN

Alternatively, you can specify them in the file '/data/local.prop' as follows:

log.tag.MyAppTag=WARN

Later versions of Android appear to require that /data/local.prop be read only. This file is read at boot time so you'll need to restart after updating it. If /data/local.prop is world writable, it will likely be ignored.

Finally, you can set them programmatically using the System.setProperty() method.

The easiest way is probably to run your compiled JAR through ProGuard before deployment, with a config like:

-assumenosideeffects class android.util.Log {
    public static int v(...);
}

That will — aside from all the other ProGuard optimisations — remove any verbose log statements directly from the bytecode.