In order to avoid having your mail returned from the prison mail room, follow the BOP guidelines. You may be asking? This has to do with Federal Correctional Institutions (FCI).

Why NO STICKERS including for return address?

FCIs and USPs host a large number of actual criminals (unlike J6ers) and stickers may have been used to send drugs. No glitter as well.

Why WRITE ON ONLY ONE SIDE OF PAPER?
Inmates do not actually receive your letters. Everything is scanned in black and white.
We suspect that the BOP is using old types of printers/scanners, and it would be too much work to scan both sides in black and white. The mail is scanned, and a copy is given to the inmate. They do not get the actually mail.

Why NO CARDS?*
It is hard to understand that one but possibly it is too hard to add to the scanner as they are a different size and also, they are both sided.
One thing you can do is scan your card and send the scanned version. Again, only one side of the paper has to be used. You might as well scan in black and white since this is what they will get.

Do not expect to receive a prompt answer from your J6er. J6ers are designed as domestic terrorists and their mail is reviewed in case you and them would be plotting some insurrection – what a sad joke but this is the narrative their follow.

DO NOT SEND ENVELOP WITH STAMPS

Not sure about this rule but one could be because stamps could be laced with drug and also because the commissary sells stamps and envelopes.

Prisons are a whole different world. Please continue to support J6ers in their time of incarceration. Mail is one of the most important things you can do besides supporting them financially for their appeals or their commissary.

*DC-CTF also known as the DC Gulag allows cards and mail written on both sides of the paper. No glitter or stickers are allowed.