do I have to wash the blisters before sending them? TWO OF A KIND April 22, 2021 12:28 Updated No you don’t! Just ensure they are dry before putting them into the envelopes. Related articles how can I help? i'm not staying in Singapore, can I still mail my blisters to to you? where are the advocate drop off locations and timings? how does your trial work? can I use my own envelopes to mail the blisters? Comments 0 comments Article is closed for comments.