how many times do you use the same batch of trap dye? that is do you save it and use it again and if so for how long?

If you are referring to logwood type trap dye for the cost of it I would just make new every season. The water will get moldy and may sour a bit from sitting around without use for several months in heat. At least that has been my experience up here.

If you want to recycle it, I would strain it through a window screen type screen and bottle into old clean gallon jugs or clean buckets with lids and place in a cool place until next use. It may hold like that, but I never stored any trap logwood dye too long.

It is just too easy and economical to get other material to start a fresh batch.

You can also use sumac, walnut hulls or other tannic acid containing materials that will dye rusted traps nicely.

Thanks

I have saved dye, Logwood and Walnut/Sumac and never had a problem with it. Any mold etc, will smell natural, just like the woods.