I have not been a "per washer" until now.....to check for bleeding I would simply cut a piece of the fabric and put in a cup of hot water, if water turned color then I would decide whether to proceed w/using/prewashing or replace, but after reading about fabric being sprayed w/pesticides or whatever is used to stop "vermin" from entering the USA, I will now wash all. Taking that thought one step further....how many more things are treated for "vermin" that we purchase and are exposed to.....makes me almost paranoid thinking about it