Pictures always help but as quilters we are often handed stuff that we don't know what to do with/don't want to do anything with! There are pretty good threads in the Help section covering most of the issues,
https://www.quiltingboard.com/qb-help-center-f27/
Discolored blocks can be soaked or otherwise washed before or after putting together. Yes, is not ideal but sometimes we gotta do what we gotta do -- and other times we just ignore whatever that stain might be...
First, there is nothing wrong with keeping them for a bit yourself, whether to work up skill or ideas. I'm a believer in "finished beats unfinished" and have no problems at all doing machine sewing or quilting on unfinished tops. Sometimes I find lovely hand stitched tops at the thrift store, often made with poly blend fabrics that the quit police won't finish even though they have been hand stitched.
Do you belong to a guild or a group? Or do you have a regular quilt shop you hang out at and can ask questions? There are always people who actually like working on things like this (but who usually have way too many of their own projects to do), who can maybe suggest settings or give you time periods or other info.