I have used those little cloths pin type plastic clips to hold my block pieces together....I also have used various paper clips both the slide on type and the clip on type....they do wrinkle the fabric a bit but don't make any holes.....I don't know however which of the metal paperclips might rust.....you can also rip the sticky part of envelopes off and use those to hold the pieces together if they are small enough...or baggies too...