vcquan

I have received 21 blocks of vintage/antique, hand-pieced blocks and before I dive into washing, pressing and putting them into a qult I'd like some advice from ya'll.
The blocks look like they have been washed but the Niece of the quilter is not sure. They have been stored in an attic and some have stains (assume that is why someone may have washed them).
As you can see from the pics, they are VERY wrinkled and some seams have started to fray (probably from washing and handling). Initial questions:
- Should I wash with my fav Retro Clean before piecing them together or after the quilt is finished (scared the red will bleed )!
- If I don't wash, can I lightly press in order to measure and piece precisely.
- Regarding piecing, I was thinking of adding sashing to 'stabilize' the blocks. Should I use GOOD cotton muslin or quilt fabric? The blocks are pieced or appliqued using very thin cotton.

Thank you so very much for any advice you can provide. I will share my progress if ya'll would like to see...
Photos to follow