My application was generally using 15-20 Mb of memory.
Last week it was chewing up 1 to 1.5 Gb Memory.
I tried all sorts of fixes - nothing worked.
I decided to uninstall Meteor (on Windows 10). The process took about a whole day. Removing the contents of AppData/local/.meteor directory is a nightmare, because Windows gets stuck with the long path names that it cannot delete.
Once .meteor/packages directory was clean I uninstalled meteor, but the reinstall and restart of my application took almost another day as meteor-tools took hours to download. I have heard there are issues with the CDN. I am currently in Israel, so might be feeding off the Asia CDN nodes.