Thanks, Anne, that's helpful to know. (-:
>>it has become quite obvious that both terms are used in AE as well as BE
No, it hasn't. So far there's one link (but no citation) apparently supporting 'scrap paper' in AE. That's it.
No one has yet suggested that 'scratch paper' is used in BE, and one reliable BE native speaker (Anne) says it isn't.
The native-speaker survey so far is admittedly very small, but at least wpr, Anne, and I all seem to have the same impression.
The only votes for 'scrap paper' in the sense of Schmierpapier in AE are from Cor (unregistered, unfamiliar), and from bike_helmut, a German speaker, for CanE.
He may well be right that Canadians follow BE on this one, but it wouldn't hurt to get that confirmed by a Canadian dictionary or by RES-can, Bob C., AGB (de/can).
I'm still a bit more skeptical about AE in general, apart from Canada. It may be that some AE speakers do use 'scrap paper' to mean scratch paper, but if that's the case, I would expect there would be other regular users who could confirm that it's really widespread enough in AE to justify removing the BE tag.