How long for "coffee grounds" on the arms to clear post IPL?

Hands and Arms can take 7-10 days for the "coffee grounds" to flake off. It can even take 14 days on the hands. These areas are further away from your heart and will take a bit more time. This is very common. It is true that higher vascularized areas (like the face) heels quicker.

It can take several weeks for laser results to settle. I recommend following up with a cosmetic dermatologist for after care recommendations. I recommend skin care with vitamin c, b5 hydrator, silicone based scar gels with growth factors and enzymatic washes with papaya enzyme to give improvement. PDT therapy can calm inflammation. Sun protection is essential. Lasers work best in combination with other treatments in order to improve the skin's texture and collagen. Best, Dr. Emer

You're correct in that the recovery time for the arms, hands or chest is typically longer than that of the face. This is due in part to faster cell turnover on the face compared to other areas of the body. The 'coffee grounds' should begin to flake off 10-14 days post treatment. Make sure to use adequate sun protection until then (and beyond!) 

As an IPL provider and patient, the coffee grounds mean that the IPL did target the brown spots and some layers of the pigmented dermis will flake off. It can take 10-14 days for it to flake off.  Be patient as it is well worth it.

You've done your research! There's so much benefit to treating body skin as well as just the face, neck and chest, but you are entirely correct. Due to differences in blood flow and cell turnover, it typically takes about 2 weeks for coffee grounds to fall off on arms, hands and other body skin and it can take even longer in some. Keep the areas moisturized and strictly out of the sun and you should get a great result!