Salvage an off flavor barch?

I brewed a Irish red from extract. It was in the primarily for one week. One week and secondary. Then kegged it. Found it to happen off flavor. A plastic or medicinal flavor. Some of my friends think it has a butter butterscotch flavor. I think its a diacetyl problem. I have detected a similar tastes and some other batches. I'm still new at this. So I think maybe something in my procedures or equipment. Is there a way to salvage this batch or do I need to toss it out? How can I prevent this or troubleshoot this?

 

I wouldn't toss it out. I've made some batches that didn't come out right and I just mix them in with another beer.

 

. Stupid phone.