How to clean pine cones to se on a wreaths

http://tipnut.com/how-to-prepare-preserve-pinecones/

https://makeanddocrew.com/how-to-clean-pine-cones-for-crafts-see-ya-bugs/

Here's an article that gives pretty much step-by-step directions plus it has ideas to do things like whiten them and how to preserve them.

http://tipnut.com/how-to-prepare-preserve-pinecones/

Oops, I see that Janet and I found the same website at just about the same time. Here's another one with exact step-by-step directions. Best of luck with your wreath project!

https://www.wikihow.com/Clean-Pine-Cones

Drying & Opening Pine Cones

1. Preheat oven to 200 degrees. Line a cookie sheet with aluminum foil and spread pine cones across it in a single layer. ... let them cook for several hours (keep watching them as long as the oven is on).
2. Remove from oven and let them rest for a couple days before cutting or using in crafts.

This drying process will kill any bugs and melt the sap due to the heat.

NOTE: To get the sap off the pine cones, first shake all of the dirt off. Then wipe the sap off with rubbing alcohol on a Q-Tip. Then soak them briefly in a mixture of vinegar and water - let them dry.

I just did this (baked) a bunch of pinecones (100's) at 200 degrees for over an hour, the sap came out (I made a mistake and did not put foil or parchment paper down first time. I would still be working on them if the I did the qtip thing. I did pick all debris (mostly pine needles) off first.