It is true that transferring flammable liquids that air pressure is in the container. This happens n portable tanks.

In a laboratory (that is not a food laboratory designed for tasting) is it never acceptable to taste a chemical because you cannot know for certain that it is not hazardous. You can be misinformed about a hazard, the container can be mislabeled, or the material can be contaminated with a hazardous materials, for example.

ao certificate doesn't exist. ao means Acceptable Offshore which is just a title to a container that is "iffy" and is given a temporary certificate

You can do so using air and/or shaking/tilting/straining the container. The rocks are heavier than the ping pong balls. So you can shake the rocks to the bottom then tilt the container into another container. Or, after the shaking, you can use compressed air to remove the balls. Another approach would be to dump the bowl into an acceptable strainer, assuming the balls are larger than the rocks.

Most anti-freeze should be acceptable for a motorcycle. Unless it states on the container not to use it in a motorcycle or not to use it with aluminum, it should be fine in your bike.