I have 400 series standard gauge passenger cars. I'm missing some steps and couplers.

I see 300 series standard gauge passenger cars on ebay that have these items. Will the 300 series work with the 400 series passenger cars?

Also, if anyone on this site has any of these items let me know.

Thanks

How do I add photos?

I have a Lionel 380E standard gauge train set that I would like to run along the wall in my man cave.

I would like to make it look as nice as possible so what is the best way to clean the cars inside and outside?