That is general cleansing guidance for original Relief Sun, not a special removal instruction, which spares the product name from becoming a household chore. The Canadian Relief Sun Aqua Fresh Rice + B5 SPF50+ PA++++ is a separate version whose directions tell you to use a water resistant sunscreen for swimming or sweating.12

When is a second cleanser useful?

If you wear Relief Sun without makeup, start with a single gentle cleanse. An oil cleanser can help break down sunscreen residue and waterproof makeup before a water based cleanser, which is one occasion when waterproof is not the desired outcome.1

The SPF number describes sunburn protection. Water resistance is a separate label claim, so check the actual sunscreen you wore rather than using SPF50+ as your reason to wash twice. In the United States, water resistance means tested protection on wet skin for 40 or 80 minutes.3

How to double cleanse if you need it

  1. 1Gently massage an oil based cleanser into your skin to loosen sunscreen, makeup and excess oil.
  2. 2Rinse with lukewarm water, leaving your skin damp.
  3. 3Gently massage a water based cleanser into your damp skin.
  4. 4Rinse and pat dry with a soft towel.
1

For makeup removal, micellar water followed by a water based cleanser is another option, which is a surprisingly flexible arrangement for a routine with a number in its name. Avoid harsh, heavily drying or fragranced cleansers whichever method you choose.1

What if your skin is sensitive or oily?

For dry or sensitive skin, choose a gentle, unscented water based cleanser; cream cleansers are less drying than foaming cleansers. Stop the extra wash if it causes dryness or irritation. Overwashing can damage the skin barrier, the protective outer layer of your skin.1

Oily skin is not an automatic reason to add an oil cleanser. Double cleansing helps some people with oily skin but causes breakouts in others. A mild, unscented foaming cleanser is a reasonable starting point. Avoid hard rubbing, washcloths and rough scrubs: irritation can increase oil production.4

For oily skin, washing morning and evening and after exercise is different from washing twice in one session. Keep moisturizing rather than trying to dry away every trace of oil. If oily skin remains troublesome despite routine changes for a month or two, seek medical help choosing products or treatment.4

Where this answer comes from

  1. 1Double Cleansing Method Explainedhealth.clevelandclinic.org
  2. 2Relief Sun Aqua-Fresh Sunscreenca.beautyofjoseon.com
  3. 3How to decode a sunscreen labelaad.org
  4. 48 Tips To Get Rid of Oily Skinhealth.clevelandclinic.org